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Author: 


Roe,  Joseph  Wickham 


Title: 


The  mechanical 
equipment 

Place: 

New  York 

Date: 

[1 922] 


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Roe,  Joseph  Wickham. 

The  mechanical  equipment,  by  Joseph  W.  Eoe  . . .    New 
York,  Industrial  extension  institute,  incorporated  t*i918i 

^    xviii,"^5l3  p.    illus.    19i"°.    (Factory  management  course, -r;  3 ^^^^  / 


Added  t.-p. :  Factory  management  course  and  service  ...  written  for  the 
Industrial  extension  institute  ... 


I.  Machinery.        i.  Title. 

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Copy  2. 


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LIBRARY 


School  of  Business 


FACTORY  MANAGEMENT 
COURSE  AND  SERVICE 


A  Series  of  Interlocking  Text  Books  Written  for  the 
Industrial  Extension  Institute  by  Factory  Man- 
agers and  Consulting  Engineers  as  Part 
of  the  Factory  Management 
Course  and  Service 


INDUSTRIAL   EXTENSION    INSTITUTE 

INCORPORATED 

NEW  YORK 


ADVISORY  COUNCIL 


Nicholas  Thiel  Ficker,  Pres., 

Charles  E.  Funk,  Secy., 

Chas.  a.  Bbockaway,  Treas., 

Alwin  von  Auw, 

Oen,  Mgr.  Boorum-Peaae  Co, 

Charles  C.  Goodrich, 

Ooodrich-Lockhart   Co, 

WiLLARD   F.    HiNE, 

Consulting  Appraisal  Engi- 
neer, Chief  Gas  Engr., 
Public  Service  Comm, 
N.  Y, 


Charles  P.  Steinmetz, 

Chdef    Consulting   Engineer^ 
General  Electric  Co. 

Jervis  R.  Harbeck, 

Vice-Pres.  American  Can  Co. 
Benj.  a.  Franklin, 

Vice-Pres,  Strathmore  Paper 
Co.,  Lieut.  Col.  Ord- 
nance Dept. 

Charles  B.  GIoing, 

Formerly  Editor,  The  Engi- 
neering Magazine,  Con- 
sulting Industrial  Engi- 
neer, 


THE 
MECHANICAL  EQUIPMENT 


BY 


JOSEPH  W.  ROE,  M.E. 

Assistant  Professor  Mechanical  Engineering  Shield 
Scientific  School,  Yale  University 


STAFF. 


C.  E.  Knoeppel, 

Prea.   C.   E.  Knoeppel  &   Co.. 
Consulting  Engineers. 
Meteb  Bloomfield, 

Consultant  on  Personnel. 
Geoboe  S.  Arm  strong, 

Consulting   Jnausirial   Engivkeer, 

H.    B.   TWYFOED, 

Purchasing  Agent,  Nichols  Cop- 
per Co. 

Nicholas  Thiel  Fickeb, 

Consulting  Industrial  Engineer. 

DwiGHT  T.  Fabnham, 

Consulting  Industrial  Engineer. 

Willabd  L.  Case, 

Pres.  Willard  L.  Case  &  Co., 
Consulting  Engineers. 

Davh)  Moffat  Myers, 

Origgs  &  Myers,   Consulting 
Engineers. 

Joseph  W.  Roe, 

Prof.   Machine  Design,   Sheffield 
Bcientiflo  School,  Yale  Univ. 
Albert  A.  Dowd,  ■ 

Consuting  Engineer. 

William  P.  Hunt, 

Consulting  Inaustrial  Engineer. 
Chablis  W.  MoKat, 

Appraisal  Engineer 


Organization   and   Administba- 

TION. 

Labor  and  Compensation. 
Planning  and  TimetStudy. 
Purchasing  and  Storing. 

Industrial  Cost  Finding, 
Executive  Statistical  Control 
The  Factory  Building. 

The  Power  Plant. 

The  Mechanical  Equipment. 

Tools  and  Patterns. 

Handling  Material  in  Factor- 
ies. 

Valuing  Industbla.l  Pbopebties. 


J   . 


VOLUME  9 
FACTORY  MANAGEMENT  COURSE 


INDUSTRIAL    EXTENSION    INSTITUTE 

INCORPORATED 

NEW  YORK 


«  ^r  Q     I    ^ 


.o„ 


*«'.-,..i«'*~"""°  ""^ 


TXT^.,«         Copyright,  1922,  bv 
INDUSTRIAL  EXTENSION  INSTITUTE 

•     •  INCORPORATED 


3   ^3  5- 


PREFACE 

The  purpose  of  this  book  is  to  present  the  standard  ma- 
chines and  mechanical  methods  used  in  general  manufactur- 
ing, and  to  show  their  proper  fields. 

An  industrial  executive  deals  with  two  general  classes  of 
problems :  those  relating  to  business,  accounting  and  executive 
management,  and  those  involving  the  physical  equipment  and 
methods  of  manufacture.  It  is  not  necessary  that  an  execu- 
tive be  able  to  build  every  machine  he  uses,  or  even  that  he 
know  all  its  habits,  good  and  bad,  as  intimately  as  the  skilled 
mechanic  who  runs  it.  But,  in  order  to  act  intelligently,  he 
must  know  the  types  of  machines  available  for  the  work  in 
hand,  their  capacity  and  relation  to  each  other,  and  the 
processes  and  methods  involved. 

Modern  industrial  equipment  is  almost  as  varied  as  the 
industries  themselves,  and  no  single  volume  could  attempt  to 
describe  all  of  it.  This  book  is  therefore  confined  chiefly  to 
the  machine  shop.  As  Mr.  F.  A.  Halsey  has  said:  "The  ma- 
chine shop  is  the  center  from  which  all  modern  industries 
radiate.  From  the  brickyard  to  the  flying  machine,  from  the 
sawmill  to  wireless  telegraphy,  from  the  stone  quarry  to  the 
moving-picture  camera,  there  is  no  modern  industry  more 
than  twice  removed  from  the  machine  shop."  Even  with  the 
field  so  narrowed  it  is  necessary  to  confine  the  attention  to 
typical  machines  and  to  avoid  too  detailed  discussion. 

So  far  as  the  writer  knows  no  book  has  yet  presented  the 
subject  of  machine  equipment  as  a  whole,  or  has  pointed  out 
the  relations  of  the  standard  tools  to  each  other.  It  is  the 
purpose  of  this  book  to  do  so.  It  is  an  outgrowth  of  a  course 
of  lectures  and  recitations  given  for  a  number  of  years  to 


vt 


PREFACE 


the  students  in  Mechanical  Engineering  at  the  Sheffield 
Scientific  School,  Yale  University,  and  presupposes  only  such 
technical  knowledge  or  experience  as  might  be  possessed  by 
an  undergraduate  in  a  technical  school  or  an  office  man  hav- 
ing a  general  familiarity  with  manufacturing. 

While  the  book  deals  chiefly  with  foundry,  forge  shop,  and 
machine  shop  equipment,  four  chapters  have  been  added  to 
point  out  the  more  characteristic  features  of  wood-working, 
paper,  shoe,  and  textile  machinery.  In  the  preparation  of 
these  four  chapters  the  writer  would  acknowledge  his  in- 
debtedness to  Mr.  Everett  0.  Waters,  of  the  Sheffield  Scientific 
School. 


Sheffield  Scientific  School, 
Yale  University. 


Joseph  Wickham  Roe. 


TABLE    OF    CONTENTS. 


CHAPTER  I 

BUILDING  AND  MANUFACTURING 

PAGE 

"M     Distinction  Between  the  Two  Systems 1 

The  Building  Method 2 

The  Manufacturing  Method 3 

Tools  Used  in  Building 4 

Tools  Used  in  Manufacturing 5 

The  Interchangeable  System 6 

Combination  Methods 11 

CHAPTER  II 

THE  DRAFTING  DEPARTMENT 

Functions 13 

Design  of  Product 14 

Design  of  Plant  Equipment 14 

Standards,  Drawings,  and  Lists 15 

Record  of  Work  Done 16 

Estimating .  17 

Supplementary  Functions 17 

Personnel 18 

Policies 19 

Practice 23 

Tools  Available 24 

Checking 24 

Blueprints 25 

Filing 25 

vii 


/ 


mil 


TABLE  OF  CONTENTS 


Changes  and  Alterations       ........  26 

Equipment V    '      '      *       ^ 

Location  of  the  Drafting  Room      ......     *      27 

CHAPTER  III 

THE  PATTERN  SHOP 
Function  and  Location qq 

Balance  of  Pattern  Makers' and  Holders' Time  "       30 

Types  of  Patterns •     •     • 

Gated  Patterns 04 

Pattern  Material •     •     •     .     » 

Allowances \  *       ^- 

Warping  and  Splitting   ...  **''.*     * 

Fillets '.'.]'''       38 

Core  Prints 

Marking  and  Painting     .....'.*.*'*       30 

Pattern  Storage oq 

Index  System 

Records      ... 

40 


CHAPTER  IV 

FOUNDRY  METALS  AND  FOUNDRY  BUILDINac- 

Metals 

Grey  Iron 

Chilled  Iron 

Malleable  Iron 

Cast  Steel       .....*.*.'.* 

Alloys    .... 

Foundry  Buildings  and  Equipment 

Storage       

Transportation      ... 


41 
41 
42 
43 
43 
44 
45 
49 
49 


TABLE  OF  CONTENTS  ix 

CHAPTER  V 

FOUNDRY  MOLDING  METHODS 

PAGE 

Materials 52 

Molding  Sands 53 

Loam 54 

Facing        54 

Cores  and  Core  Binders 55 

Cope  and  Drag 56 

Small  Tools .  57 

Making  a  Mold .  58 

Machine  Molding '    .     .  60 

Carrier  Foundries 63 

CHAPTER  VI 

FOUNDRY— MELTING,  POURING,  CLEANING 

General  Methods 65 

The  Cupola           65 

The  Air  Furnace 70 

Open-Hearth  Furnace 71 

Oil  or  Gas  Furnaces 71 

Crucible  Furnace 72 

Electric  Furnace 75 

Ladles         75 

Pouring .  76 

Defects  of  Castings 76 

Cleaning .  78 

Tumbling         78 

Pickling 79 

Sand  Blast 79 

CHAPTER  VII 

FORGING  METHODS 

Hand  Work 80 

The  Forge .  81 


i 


«  TABLE  OF  CONTENTS 

Tuols ^^^^ 

Operations .*.''*  86 

Welding .*     *     .*     \     \     \     \     \  37 

Steam  Hammer  Work .'.'*'  88 

Power  Hammers •     •     •     .     . 

Headers  and  Upsetters .*.*!'*  94 

Hydraulic  Press .".'.'!*  94 

Rolling \     .     \     \     \  97 

I^rawing 99 

Extrusion  Process     ......     i     *     '     *     *  inn 

Pipe  Bending .'.'.'.*.*  100 

CHAPTER  VIII 

DROP  FORGING 

Utility       102 

Drop  Hammer ^qo 

Trimming  Press    ....                '     '     *     '     '     *     mc 
T^.  lUo 

^!^« 107 

Die  Working ^^q 

Heating .'.*.'.'.'.'*  114 

The  Forging  Operation .'.'''  114 

Pickling .'.*.'.'.'  115 

Cold  Trimming ]]'*''  -^^ 

General  Considerations .'     1     !     '     *  116 

CHAPTER  IX 

WELDING,  SOLDERING    AND  BRAZING 

General  Classes  of  Welding jj^ 

Pressure  Welding  by  Hammering  .     .     .'     .*     .'     .'     ]  119 

Electric  Resistance  Welding     ....!.'.'.*  122 

La  Grange-Hoho  Process .'.'.*'  127 

Electric-Arc  Welding      .....'.'.*.'.'*  128 

Gas-Flame  Welding        •     ,     .     .*     .*     .'     .'     ,'     .'     .'  130 


TABLE  OF  CONTENTS 


x\ 


PAGE 


Advantages 233 


Uses 


133 


Thermit  Welding ^33 

Soldering  and  Brazing 235 

Brazing  Process ^36 

CHAPTER  X 

HEAT  TREATMENTS 

Variability  of  Steel  Properties 133 

Heat  Treat  Processes 139 

Hardening j^q 

Heating ^^^ 

Quenching ^^ 

Self-Hardening  Steels 143 

Taylor-White  Steel .'.'!!!  149 

Annealing        jcq 

Tempering ^r-. 

The  Color  Scale    .,.!!!.'!     .'     ]     ."     \     151 
Carbonizing j^q 

CHAPTER  XI 

THE  TOOL  ROOM— FIXTURES  AND  GAUGES 

The  Tool  Room  a  Modern  Development 

Relation  of  Tool  Room  to  Shop 

Functions  of  the  Tool  Room 

The  Tool  Storeroom 

Machine  Equipment 

Policies       .... 

Fixtures  and  Jigs      . 

Economic  Principles 

Mechanical  Principles 

Gauging      .... 

Types  of  Gauges 

General  Considerations 


155 

155 

156 

158 

159 

160 

160 

161 

162 

164 

165 

169 


^**  TABLE  OF  CONTENTS 

CHAPTER  XII 

CUTTING  TOOLS 

Material ^^^^ 

Carbon  Steel         .     .     . ]l\ 

Mushet,  or  Self-Hardening  Steel .79 

High-Speed  Steels      .     .  .^^ 

The  Lathe-Planer       .      .  ^^^ 

Multiple  Tool-Holders     .     [ :lt 

Single-Edged  Forming  Tools .70 

Milling  Cutters     .      .                       ]V: 

Gang  Mills      .....*.*; JJJ 

Speeds  and  Feeds  '10^ 

Drills '      ' ^^' 

Reamers     ....  

Taps      . ^^^ 

Dies  .  .  :  :  ; ^^^ 

Punches      .     .  ^^^ 

Shears        .      .      *     '     * ^^^ 

Saws      .......'.' ^^^ 

Cutting  Lubricants     ...*.' l^l 

CHAPTER  XIII 

LATHES 

i^evelopment  of  the  Lathe 20O 

Henry  Maudslay  and  Modern  Tools onn 

The  Speed  Lathe .'•'.'*"  203 

The  Engine  Lathe     .     .  oni 

Head-Stock      .  f"* 

Speeds        ....!.'.' f^ 

Spindle  and  Tail  Stock   .      .' l^l 

Slide  Rest       .  "^"^ 

210 

Change-Gear  Box *     '     '      '     ^10 

Single  Driving  Pulley     ....'...*'     012 


4 


TABLE  OF  CONTENTS 


Xlll 


PAGE 

Mounting  the  Work 212 

Tool  Post 214 

Special  Lathes 215 

Lathe  Operation        215 

CHAPTER  XIV 

TURRET  AND  AUTOMATIC  LATHES 

The  Turret  Principle 219 

Turret  Lathe  vs.  Engine  Lathe .220 

Hand  and  Automatic  Turret  Lathes 221 

Multi-Spindle  Automatics 222 

Hand-Operated  Turret  Lathes 223 

Gisholt  Lathe 226 

Warner  and  Swasey  Lathe 228 

Hartness  Flat-Turret  Lathe 229 

Principle  of  Automatic  Lathes 232 

Gridley  Automatic  Lathe 236 

Multi-Spindle  Automatics 238 

Fay  Automatic  Lathe 240 

Lo-Swing  Lathe 243 

Blanchard  Lathe 244 

CHAPTER  XV 

BORING 

Wilkinson 's  Boring  Machine 245 

r^>oring  Mills  Classified *     !     !     !     .  246 

Vertical  Boring  Mill  versus  Lathe       ......  247 

Vertical  Boring  Mill  versus  Planer      .....!  249 

Construction  of  Vertical  Boring  Mill        ....      .*  251 

Table,  Drive  and  Tools !     .     .     .  255 

Bullard  Mult-au-matic  Vertical  Lathe      \     ,     .     .     .  256 

Horizontal  Boring  Machine .'     .'     .  258 

Similarity  to  the  Lathe        ....!.*!!.*  260 


X 


XIV 


TABLE  OF  CONTENTS 


An  Adaptable  Type 260 

Portable  Boring  Machines 263 

CHAPTER  XVI 

DRILLING  MACHINERY 

The  Sensitive  Drill 266 

Upright  Drills *  268 

Details  of  the  Drive 269 

Heavy  Duty  Drill-Presses 270 

Radial  Drills        ..!!.*  273 

The  Column  and  Drilling  Mechanism 274 

Multiple-Spindle  Drill !     .     .  278 

Drilling  Jigs .      !  279 

Work  Commonly  Done  on  Drill  Press       .     .      .      .     .*  281 

CHAPTER  XVII 

PLANERS,  SHAPERS,  AND  SLOTTERS 

Definition  of  Field 283 

Early  Types  of  Planers !     !     !  284 

The  Modern  Planer .*     !     !  284 

Standard  Type  of  Planer ..."  285 

Rack-and-Pinion  Drive 286 

The  Uprights .     .'  289 

Feed  Motions        .     .     .     . 290 

Special  Types  of  Planers .'292 

The  Shaper  and  Its  Work 297 

Construction  and  Operation  of  the  Shaper    ....  299 

The  Traversing  Shaper \  302 

The  Vertical  Shaper,  or  Slotter 305 

CHAPTER  XVIII 

MILLING  MACHINES 
Some  Advantages  of  the  Milling  Process  .     .     ...     .     308 

The  Work  of  the  Milling  Machine .308 


TABLE  OF  CONTENTS  xv 

PAGE 

lOrigin  and  Development  of  Milling  Machine      ...  ^09 

[The  Lincoln  Type 313 

JThe  Briggs'  Type 314 

Modern  Development  of  Lincoln  Miller 316 

Column-and-Knee  Type 317 

Vertical  Miller 3^9 

Profile  Milling  Machine 322 

Universal  Milling  Machine 324 

Milling  Teeth  of  Spur  Gear 327 

Milling  Long  Spirals 327 

Control  of  Rotary  Motion 327 

Continuous  Rotary  Feeding 323 

Planer  Type  of  Milling  Machine 329 

Rotary  Planer 332 


CHAPTER  XIX 

GEAR-CUTTING 

Two  Systems  of  Tooth  Forms   ........  334 

Spur  Gears 335 

Helical  Gears 337 

Bevel  Gears 337 

Worm  Gears 337 

Formed-Tooth  Principle 333 

Template  Principle 34^ 

Form-Generating  Principle 343 

Spur-Gear-Cutter 345 

Machine  Embodying  Template  Principle        ....  346 

Fellows  Gear-Shaper 343 

Hobbing  Machines ^51 

Cutting  Helical  (Jears 353 

Cutting  Bevel  Gears 354 

Machine  Embodying  Form-Generating  Principle      .     .  357 


/ 


( 


^^«*  TBALE  OF  CONTENTS 

CHAPTER  XX 

SCREW-THREAD-CUTTING 

Early  Methods  of  Cutting  Screw  Threads     ....     360 

Standardization  of  Screw  Threads 361 

Types  of  Screw  Threads 351 

Cutting  Screw  Threads 354 

Bolt-Threading  Machines 355 

Opening  Die  Heads         355 

Pipe-Threading  Machines 359 

Thread-Cutting  on  Lathes 371 

Milling  Screw  Threads 374 

Rolling  Threads         375 

CHAPTER  XXI 

GRINDING,  AND  GRINDING  MACHINERY 

Development  of  the  Grinding  Process 377 

Special  Advantages         377 

Grinding  Abrasives         373 

Grinding  Wheels       .     .     . 330 

C^rading 381 

Selection  of  Wheels         332 

Mounting  of  Wheels 333 

Types  of  Grinding  Machines     ........  386 

Tool  Grinders        . 395 

Polishing  and  Buffing 397 

CHAPTER  XXII 

BROACHING  AND  PRESS  WORK 

The  Broaching  Process ogg 

The  Broaching  Machine 400 

Broaching  Tools ^q2 

Punches  and  Dies ^5 


TABLE  OF  CONTENTS 


xvtt 


Types  of  Presses ^qq 

^^^'^y    •:•••••'.'.*!!.■.*  414 

CHAPTER  XXIII 

WOODWORKING  MACHINERY 

Types  of  Machines,  Few :  Modifications,  Many    ...  416 

Saws !     .  417 

Band  Saw '  .^r. 

Circular  Saw '  a^c^ 

Universal  Saw  Bench aoq 

Swing-Frame  Saw "     '  421 

Log  Mill '     ....  421 

Gang  Saw 423 

Power  Consumption  of  Saws ,  424 

Planers,  Surfacers,  Moulders  and  Shapers                  '      *  424 

^"*^^\      • .*.'.*     430 

Gauge  Lathe .09 

Blanchard,  or  Copying,  Lathe .'     .'     .     432 

Miscellaneous  Machines '     .*  434 

CHAPTER  XXIV 

PAPER  MACHINERY 

Rag  Machinery ^  ^^g 

Dusters  and  Cutters .'  .'  "     439 

Digesters  and  Washers .'  *     441 

Wood-Pulp  Machinery .*  .  "     *     444 

Beaters  and  Refiners .'  .*          447 

Paper  Machines .'  '  '           448 

Finishing  Machinery .'.'.'.     456 

CHAPTER  XXV 

BOOT  AND  SHOE  MAf^HINERY 

General  Characteristics 459 

History  of  Shoe  Machinei  y !     .*     459 


V 


f 


XVll% 


TABLE  OF  CONTENTS 


f 


PAGE 

Machine  Operations 46I 

Arrangement  of  a  Shoe  Factory 462 

Types  of  Shoes 462 

Cutting  Room  Machinery 464 

Stitching-Room  Machinery         468 

Machinery  of  the  Stock-Fitting  Room 472 

Bottoming-Room  Machinery 474 

Finishing-Room  Machinery 473 

CHAPTER  XXVI 

TEXTILE  MACHINERY 

The  Fibres  and  the  Processes 48I 

Cotton-Spinning  Machinery 431 

The  Comb 434 

Drawing  Frame ;  Fly  Frame ;  Spinning  Machine     .      .  485 

Wool-Spinning  Machinery 439 

Worsted-Spinning  Machinery 490 

Linen  and  Silk  Preparation 493 

Weaving  Machinery 494 

Mechanism  of  the  Loom 496 

Weaving   Intricate  Patterns 499 

Knitting  Machines \     .501 

Finishing  Machinery 503 


THE  MECHANICAL  EQUIPMENT 


CHAPTER  I 
BUILDING  AND  MANUFACTURING 

Distinction  Between  the  Two  Systems.— Two  well- 
I  defined  methods  of  production  are  found  in  the  metal 
.trades,  and  the  principles  which  differentiate  them 
run  through  all  forms  of  factory  production.  No  gen- 
lerally  recognized  names  have  been  given  them,  and 
for  want  of  better  terms  we  will  call  them  ** building" 
land  ** manufacturing."  The  two  systems  are  sharply 
differentiated  through  the  entire  process  of  produc- 
tion, and  even  to  marketing.  The  use  of  one  or  the 
other  affects  the  nature  of  the  whole  plant,  its 
methods,  and  its  equipment;  consequently  before  tak- 
ing up  the  equipment  in  detail  we  will  consider  the 
[two  systems  and  what  they  involve. 

We  shall  use  the  term  ''building,"  to  cover  the 
[production  of  machines  or  other  articles  one  at  a 
I  time,  or  in  numbers  so  limited  that  their  methods  of 
production  are  unchanged.  By  ** manufacturing"  we 
shall  mean  production  in  lots  to  standard  designs  and 
usually  with  the  corresponding  parts  interchangeable. 
As  will  be  seen  later,  the  term  manufacturing  usually 
implies  a  large  output,  but  the  distinction  lies  rather 
in  the  methods  used  than  in  the  quantities  produced. 


2  THE  MECHANICAL  EQUIPMENT 

A  firm  might  build  a  great  many  things,  or  manufac- 
ture a  few.  In  either  case  the  costs  would  probably 
be  high.  As  we  shall  see,  the  two  systems  may  be 
and  often  are  combined  in  the  production  of  articles 
where  certain  details  used  in  great  quantities  are 
manufactured,  while  the  larger  parts  which  are  not 
standard  are  built.  This  use  of  the  two  systems 
together  may  often  be  the  wisest  and  most  profitable 
method  of  production. 

The  Buildings  Method. — ^Perhaps  the  best  way  to 
bring  out  the  characteristics  of  the  building  method 
is  to  follow  the  course  of  a  large  water-works  engine. 

The  intending  purchaser  may  issue  a  set  of  speci- 
fications laying  down  the  conditions  under  which  the 
proposed  engine  is  to  operate,  the  quality  of  materials 
to  be  used,  and  the  capacity  and  economies  to  be 
guaranteed.  The  firms  quoting  will  draw  up  pre- 
liminary designs  and  estimate  upon  them,  taking  into 
account  patterns  available,  machinery  required  for 
production,  transportation,  erecting  facilities,  and  so 
forth.  A  public  hearing  may  then  be  held  where  the 
advantages  of  the  various  designs  submitted  are 
argued.  These  are  considered  and  the  contract 
finallv  let.  The  successful  firm  then  makes  the  draw- 
ings  covering  the  details  of  the  entire  machine,  the 
patterns  that  may  be  necessary,  and  casts  and  ma- 
chines the  various  parts  and  erects  the  engine  within 
its  plant.  It  is  then  knocked  down,  shipped  to  its 
destination,  erected  in  place,  and  finally  tested  under 
working  conditions.  As  this  process  requires  a  long 
time  and  heavy  expenditure,  partial  payments  may  be 
made  at  stated  stages;  but  the  engine,  even  when  in 


BUILDING  AND  MANUFACTURING  3 

place  and  running,  is  still  in  the  hands  of  the  builder 
and  is  not  accepted  until  the  performance  guaranteed 
has  been  demonstrated.  Then  and  not  until  then  is 
the  transaction  closed  and  the  final  payment  made. 

The  Manufacturing  Method.— Contrast  the  above 
with  the  production  of  a  new  model  of  sporting  rifle. 
A  firm  manufacturing  rifles  may  determine  that  a  new 
type  of  rifle  is  called  for,  or  some  design  may  be  sub- 
mitted to  them  which  they  recognize  as  desirable. 
I  Every  available  expert  is  consulted,  a  design  evolved, 
one  or  more  models   ** built,"   and   carefullv  tested 
I  under  every  possible  condition  of  use.    Any  necessary 
I  modification  will  be  made,  the  details  of  manufacture 
carefully  studied  out,  and  a  sequence  of  operations 
determined.    A  force  of  tool-makers  will  be  set  to 
work  designing  jigs,  fixtures,  gauges,  and,  if  neces- 
jsary,    special    machines.     The     building     of    these, 
together  with  the  preliminary  work,   will   run  into 
I  thousands  or  even  hundreds  of  thousands  of  dollars. 
When  actual  production  is  started  a  large  lot  will  be 
I  manufactured   and  placed   in   stock,   an  advertising 
campaign  will  be  inaugurated,  and  sales  begun.    In 
general,    the    selling     department     will     begin     its 
activities  when  the  goods  are  finished  and  placed  in 
[stock.    And  the  marketing  of  the  product  is  one  of 
[business  skill  and  judgment,  involving  little  or  no 
engineering.    In  the  case  of  the  engine,  the  sale  pre- 
cedes the  building  and  even  much  of  the  designing;, 
and  the  engineer  is  intimately  concerned  in  the  selling 
as  he  must  convince  the  purchaser  of  the  superiority 
of  his  design.    The  two  processes  of  production  from 
initial  sale  to  final  acceptance  follow  different  courses. 


V 


4       THE  MECHANICAL  EQUIPMENT 

Tools  Used  in  Building.— The  contrast  runs  into  the 
tools  used,  the  methods  employed,  and  even  to  the 
type  of  building  best  adapted.  The  building  system 
employs  what  are  commonly  called  the  standard  tools 
— the  lathe,  planer,  shaper,  slotting  machine,  boring 
mill,  drilling  machine,  and  so  on.  The  workmen  de- 
termine the  dimensions  of  the  work  and  the  adjust- 
ment of  the  cutting  tools  for  each  piece  by  direct 
measurement,  and  check  the  work  with  standard 
measuring  tools  and  calipers — operations  which  call 
for  a  skilled  mechanic.  The  building  used  for  this 
large  work  usually  contains  a  large  open  bay  (see  A, 
Figure  1)  with  complete  crane  service,  providing  room 
for  heavy  machine  tools,  work  in  progress,  erecting 
floor,  etc.  On  each  side  of  this  bay  will  be  one  or 
more  floors  (B  and  C)  equipped  with  smaller  tools, 
producing  the  minor  pieces  which  move  out  to  the 


FIG.  1.      TYPE  OP  BUILDING  ADAPTED  TO  LARGE  AND 

SPECIAL   WORK 


BUILDING  AND  MANUFACTURING  § 

center  as  the  work  is  completed.  The  middle  bay 
may  have  standard  railway  tracks  and  connections,  so 
that  the  rough  castings  may  be  brought  in  from  the 
foundry  or  elsewhere  and  the  finished  product  loaded 
on  cars  under  cover  with  the  use  of  the  crane  equip- 
ment. 

The  type  of  tools  and  the  building  system  in  general 
were  developed  in  England  a  little  over  a  century 
ago  by  early  English  mechanics,  such  as  Maudslay, 
Roberts,  Nasmyth  and  Whitworth.  In  later  years 
large  special  tools,  such  as  armor-plate  planers, 
special  drilling  machinery,  and  the  forging  machinery 
used  in  American  bridge  work,  will  be  found  in  build- 
ing plants,  but  they  are  special  only  in  so  far  as  they 
are  adapted  to  a  certain  type  of  work.  They  call  for 
skilled  attendants,  however,  and  the  size  of  the  work 
is  determined  by  direct  measurement.  Most  of  the 
standard  tools  used  in  building  were  developed  be- 
fore 1850;  since  that  time  they  have  increased  in  size, 
power,  and  precision,  but  the  essential  features  of 
their  design  remain  much  the  same. 

Tools  Used  in  Manufacturing.— When  one  turns  to 
manufacturing,  an  entirely  different  range  of  tools  is 
encountered,  and  different  methods  prevail.  Here  the 
characteristic  machines  are  turret-lathes  of  the  hand- 
operated,  automatic,  and  single-  and  multi-spindle 
types,  and  the  milling  machine.  With  them  will  be 
found  the  stamping  press,  doing  all  kinds  of  work 
ranging  from  the  roughest  to  the  extremely  accurate, 
m  the  case  of  sub-press  dies;  the  precision  grinder, 
the  drop  hammer,  and  the  broaching  machine.  On 
nearly  all  of  these  machines  the  work  is  done  with  the 


I 


6       THE  MECHANICAL  EQUIPMENT 

use  of  jigs,  fixtures,  and  special  cutters,  which  has  a 
profound  effect  upon  the  whole  working  force  of  the 
plant.  The  functions  performed  by  the  general  me- 
chanic operating  the  standard  tool  have  been  segre- 
gated into  those  of  the  skilled  tool-maker  in  the  tool 
room  and  the  handy  man  or  operative  running  the 
machine.  As  manufactured  products  are  usually 
comparatively  light,  the  large  crane  bay  is  not  needed 
and  the  building  may  be  of  the  usual  multi-floored 
mill  type  (see  Figure  2).  As  the  work  is  put  through 
in  large  quantities,  it  is  moved  on  trucks  or  specially 
adapted  racks.  Much  ingenuity  has  been  given  to 
the  subject  of  these  trucks  and  they  will  be  taken  up 
in  another  volume.* 

The  Interchangeable  System. — In  its  application  to 
the  metal  trades,  manufacturing  usually  implies  the 
use  of  the  interchangeable  system  of  production.  The 
essential  elements  of  the  interchangeable  system  are, 
first,  the  use  of  limit  gauges,  which  are  based  on  the 
application  of  the  old  principle  that  **  things  equal  to 
the  same  thing  are  equal  to  each  other."  Each  part 
manufactured  must  fit  definite  gauges,  each  of  which 
contains  two  limits  for  measuring  the  operation  to  be 
gauged.  If  it  comes  within  these  limits,  the  piece  is 
known  to  be  usable;  if  it  falls  without,  it  is  not  usable 
and  is  rejected.  By  this  means  the  individual  judg- 
ment of  the  workman  as  to  the  fitting  of  parts  is 
almost  eliminated.  The  second  element,  so  closely 
allied  to  the  first  as  to  be  almost  inseparable,  is  the 
use  of  jigs,  fixtures,  and  special  forms  of  cutters.    By 


BUILDING  AND  MANUFACTURING 


I 


"m/z/mmm/zm/m)^^ 


*See  "Handling  Material  in  Factories,"   by  William  F.  Hunt, 
Factory  Management  Course. 


FIG.   2.      TYPE   OF   BUILDING   USED   IN    MANUFACTURING    WORK 

these  the  workman  is  also  largely  relieved  of  judg- 
ment in  setting  the  work  in  the  machine  and  in  set- 
ting the  tool  in  relation  to  the  work. 

The  interchangeable  system  was  developed  by  Eli 
Whitney  a  few  years  after  the  invention  of  the  cotton 
gin.  Few  people  realize  that  Whitney,  in  addition  to 
making  possible  the  modern  cotton  industry,  de- 
veloped commercially  the  interchangeable  system  of 
manufacture  with  its  profound  and  far-reaching 
effects.  It  was  applied  by  him  to  the  manufacture  of 
muskets  for  the   United  States    Government   about 


^ 


I 


8 


THE  MECHANICAL  EQUIPMENT 


1800     Simeon  North,  of  Middletown,  Conn.,  at  almost 
the     ame   time   applied   it   to    the   manufacture   of 
pistols;  and  in  the  shops  of  these  two  men  it  was 
demonstrated  that  work  could  be  produced  commer- 
cially upon  this  basis.    From  the  gun  makers,  the 
sys  em  spread  to  the  clock  makers,  and  later,  in  turn! 
to  the  manufacture  of  sewing  machines,  typewriters 
bicycles,  automobiles,  and  the  many  high-grade  ma 
chine-shop  products  which  have  been  developed  i 
the  last  two  or  three  generations. 

Many  great  advantages  are  offered  by  the  inter 
changeable  system.    The  product  is   much   cheape; 

Iln^"^'"  /•""  ^^^^^  quantities,  is  more  carefully 
st.id.ed  out,  IS  usually  better  made  and  more  uniform 
Goods  may  be  carried  in  stock,  and  immediate  dt 
hveries  are  possible.  Many  a  sale  can  be  maleof  a 
standard  article  to  be  delivered  at  once  from  stock 
tZ\  "^^'T^  "'^^  ""-"^'^  "«"ld  require  atng 
liLTin  the    H  r.^r^'r  .'"-^  ^'l"^"^  ^'^'  «dvantagf 

ZZl^  K  i*^  *"  '*'*^^°  '■^P^''-  ?«"•*«;  f°r  these  afe 
obtamable  both  promptly  and  at  a  low  cost  from  the 

repair  stocks  carried  for  this  purpose.  This  advan! 
tage  IS  very  marked  in  the  case  of  automobiles  and 
other  articles  subject  to  breakage  and  wear  A 
standard  machine  of  proven  design  for  which  repa^ 
par  s  may  be  obtained  at  conveniently  located  dt 
tnbuting  centers  is  much  more  valuable  to  a  pur- 

Certain  limitations  more  or  less  offset  the  above 
grea  advantages,  and,  hence,  the  disadvantaels 
should  also  be  thoroughly  understood.    Ae  Tnve? 


-X 

I 

i 


JBUILDING  AND  MANUFACTURING  9 

ment  in  tools,  gauges,  etc.,  may  be  enormous,  and  be- 
comes prohibitive  when  distributed  over  a  small  out- 
put.   There  is  always  the  balance  between  the  direct 
savings  in  manufacture  over  the  building  system  on 
the  one  hand,  and  the  interest  charges,  maintenance, 
etc.,   of  the  tools   required   by   the   interchangeable 
manufacturing  system  on  the  other  hand.    While  the 
labor  costs  are  relatively  high  in  the  building  system, 
they  may  be  curtailed  in  slack  time  by  the  discharge 
of  workmen.    Under  the  manufacturing  system,  how- 
ever,  the  interest  charges  on  the  expensive  equip- 
ment go  on  whether  the  production  is  large  or  small. 
The  total  costs,  therefore,  are  much  less  flexible.    It 
follows  that  the  markets  for  a  manufacturing  opera- 
tion must  be  more  stable  than  is  necessary  in  a  build- 
ing operation.    The  great  investment  in  special  tools, 
etc.,  based  on  a  standard  output  tends  to  discourage 
minor  improvements;  and  these  special  tools  must 
show  a  large  margin  of  saving  to  pay  for  discarding 
the   old   equipment   and   the   building   of   the   new. 
Standards  once  adopted  may  become  so  inflexible  as 
almost  to  defy  change. 

Another  danger  in  the  interchangeable  system  lies 
in  the  possible  obsolescence  or  supersedence  of  the 
product.  The  bicycle  industry  is  a  good  example  of 
chis.  At  its  height,  this  industry  represented  the 
most  refined  application  of  the  interchangeable  prin- 
ciple, and  millions  of  dollars  were  invested  in  tools 
and  equipment  which,  in  a  very  few  years,  became 
almost  valueless  with  the  collapse  of  the  industry. 

It  is  evident  from  the  elaborate  preparations  neces- 
sary that  a  long  time  is  required  to  get  started;  and 


10 


THE  MECHANICAJj  EQUIPMENT 


BUILDING  AND  MANUFACTURING 


11 


if  the  preliminary  work  is  slighted  or  neglected,  dis- 
aster is  almost  certain.    It  requires  the  careful  work 
of  trained  experts— new  and  untrained  men  cannot  be 
trusted  to  do  it.     The  failure  of  so  many  American 
manufacturers  who  ** jumped  into''  the  ammunition 
business  at  the  outbreak  of  the  European  War,  is  a 
glaring  example.    Many  firms,  which  had  been  build- 
ing other  things  successfully,  took  contracts  calling 
for  quick  deliveries  and  were  utterly  unable  to  fulfill 
their  guarantees  either  as  to  quantities,  time  prom- 
ised,   or    quality   of    work.    Even    the    older    firms, 
thoroughly  familiar  with  this  type  of  manufacture, 
fell  down  when  compelled  to  expand  their  business 
many  fold  in  a  short  time.    In  one  of  the  large  com- 
panies the  inability  to  build  new  tools  and  properly 
to  maintain  both  the  old  and  the  new  tools,  caused  an 
actual  decrease  in  output  from  that  which  obtained 
before  the  sudden  strain  was  put  upon  them,  despite 
an  enormous  expansion  of  their  plant. 

The  advantages  of  the  interchangeable  system  can 
be  fully  realized  only  when  there  is  a  large,  stable 
and  homogeneous  market,  educated  to  the  use  of  the 
standardized  product.  Without  doubt,  this  is  one  of 
the  reasons  why  America  has  led  the  world  in  the 
development  of  the  system.  While  the  United  States 
has  a  vast  number  of  clever  mechanics  capable  of 
working  to  the  standards  required,  it  must  be  borne 
in  mind  that  it  also  offers  the  greatest  market  in  the 
world  with  the  greatest  purchasing  power.  American 
manufacturers,  operating  upon  the  principle  of  inter- 
changeable manufacture,  have  been  notably  slow  in 
capturing  the  foreign  market.    Articles  in  demand  in 


i 


foreign  countries  have  not  been  standardized,  and  the 
American  manufacturers  prefer  to  manufacture  for 
the  large  and  rich  home  market  rather  than  build  for 
the  diverse  and  scattered  foreign  market.  It  is  not 
so  much  that  they  have  been  neglectful  of  foreign 
opportunity  as  that  they  have  preferred  to  manufac- 
ture for  their  own  market  at  greater  profit. 

Combination     Methods.— Building     methods     will 
always  have  their  place  and  are  the  only  ones  pos- 
sible for  large  and  unstandardized  work  which  must 
be     made     to     suit     individual     conditions.     Great 
progress    has    been   made,    however,    particularly   in 
America,  in  the  partial  standardization  of  such  work 
by  standardizing  the  units  employed  and  obtaining 
some  diversity  by  the  manner  of  assembling  them. 
Nothing  could  be  more  diversified,  for  instance,  than 
the  systems  of  shafting  and  power  transmission  in 
various  plants.     The  units  which  are  employed  have 
been  standardized,  and   we  have   standard   hangers, 
pulleys,  shafting,   etc.,  which   are  combined  in  dif- 
ferent   ways    as    local    conditions    require.     Another 
example  of  this  is  the  machinery  for  handling  ma- 
terials: the  various   elements   in   conveying  machin- 
ery have  been  reduced  to  standards,  are  manufac- 
tured in  lots,  and  carried  in  stock;  widely  diverse 
installations  are  made  from  these  units  by  assembling 
them  in  framing  suited  to  meet  the  conditions.     This 
principle   is   carried  into   the   design   of   large   ma- 
chinery, and  many  factories  have  standard  details  of 
design,  such  as  standard  size  hubs  for  shafts,  stand- 
ard arms,  and  standard  dimensions  for  various  parts. 
This  enables  them  to  utilize  the  patterns,  special  tools! 


t 


12 


THE  MECHANICAL  EQUIPMENT 


and  advantages  of  manufacturing  in  what  is  other- 
wise a  varied  line  of  output.  An  example  of  stand- 
ards in  dimensions  is  found  in  the  distance  between 
the  centers  of  duplex  pumps.  The  large  manufac- 
turers have  adopted  certain  distances  between  centers, 
each  covering  a  definite  range  of  sizes,  which  enables 
them  to  machine  the  pumps  on  standard  double- 
spindle  lathes  which  finish  both  cvlinders  at  once. 
This  principle  is  of  great  importance  and  should  be 
borne  in  mind  in  all  plants  where  the  output  is  such 
that  it  can  be  applied. 

From  the  foregoing  considerations  it  is  seen  that 
the  two  methods  of  production  should  be  carefully 
considered  in  the  design  of  all  plant  equipment  and  in 
the  determination  of  the  most  desirable  methods  of 
production. 


1. 


2. 


CHAPTER  II 
THE  DRAFTING  DEPARTMENT 

Functions.— The  functions,  policies,  and  practice  of 
the  drafting  department  present  too  large  a  subject  to 
be  considered  in  detail  here.  Some  only  of  the  prin- 
ciples involved  will  be  pointed  out,  and  references 
cited  so  that  special  features  may  be  studied  else- 
where.   A  schedule  of  the  functions  is  as  follows: 

Developing  the  design  of  new  product  which  in- 
volves the  making  and  authorizing  of  any 
alterations  or  improvements  in  the  product. 

Designing  plant  equipment,  special  tools,  fixtures, 
and  gauges,  etc. 

Establishing  standards  for— 
Product,  and  elementary  details  of  the  product, 
such  as  hubs,  key- ways,  gears,  etc.; 

b.  Machines  and  tools  used  in  production; 

c.  Supplies,  such  as  screws,  fittings,  etc. 

4.    Furnishing    complete    instructions    covering    the 
above,  which  involves — 
Designs, 

Detail  drawings, 
Tracings, 

Drawing  lists  and  bills  of  material, 
Data-sheets, 

13 


3. 


a. 


a. 
b. 
c. 
d. 
e. 


Y 


14 


THE  MECHANICAL  EQUIPMENT 


DRAFTING  DEPARTMENT 


15 


f.  Cheeking  all  of  the  above  items  (a)  to  (e), 

g.  Making  blueprints. 

5.  Maintaining  a  record  of  work  done. 

6.  Sometimes  estimating  on  new  work. 

Functions  1  and  6  involve  as  supplementary  work, 
issuing,  indexing,  and  filing  the  blueprints,  sketches, 
data-sheets,  estimates,  etc.,  and  recording  changes  in 
design,  pattern  numbers,  issues  and  recalls  of  blue- 
prints, etc. 

Design  of  Product.— The  development  of  designs 
for  experimental  machines  and  studies  of  possible  im- 
provements should  be  done  under  the  supervision  of 
the  chief  engineer  or  the  chief  draftsman  with  the  as- 
sistance, in  the  case  of  very  large  concerns,  of  special 
designers  expert  in  a  particular  field.  Designers 
should  also  co-operate  with  the  shop  in  the  testing  of 
these  machines-,  and  make  such  changes  as  may  be 
shown  desirable  in  the  development  of  the  work. 

Design  of  Plant  Equipment.— In  many  companies 
much  of  the  work  covered  by  the  second  function, 
instead  of  being  performed  in  the  main  drafting 
office,  is  done  in  independent  drafting  rooms  scat- 
tered through  the  plant.  Many  reasons  exist  why 
this  work  should  be  under  the  same  general  control 
as  the  design  of  product.  Drawings  and  designs  of 
some  sort,  are  involved  which  can  be  made  most  effi- 
ciently in  the  drafting  department,  although  this 
work  can  be  separated  and  placed  into  the  hands  of 
tool  specialists  who  may  or  may  not  be  in  the  general 
drafting  room.  It  is  desirable,  however,  that  their 
work  should  **head  up''  to  the  official  in  charge  of 


the  designing  department.  If  this  is  done,  the  de- 
signs of  product  are  much  more  likely  to  be  developed 
with  proper  reference  to  the  patterns  and  tools  avail- 
able. Slight  changes  in  design  which  will  enable  the 
utilization  of  existing  tools  are  more  apt  to  be  made 
and  the  operations  of  manufacture  to  be  borne  in  mind. 
In  interchangeable  products  no  new  design  should  be 
considered  complete  until  the  entire  scheme  of  manu- 
facturing operations  and  of  gauging  each  piece  has 
been  determined  to  the  last  detail. 

Of  necessity  this  work  must  be  done  in  conjunction 
with  the  principal  shop  executives.     To  secure  the 
all-round  point  of  view  necessary,  a  ^  design  commit- 
tee    has  been  found  useful  in  some  plants,  which  may 
consist  of  the  sales  manager,  chief  draftsman,  super- 
mtendent,  tool  designer,  and  the  leading  men  con- 
cerned in  the  manufacture  of  the  proposed  work,  such 
as  the  foremen  of  the  pattern  shop,  foundry,  and 
machine  shop.    Any  proposed  preliminary  design  is 
gone  over  by  this  committee  from  the  points  of  view 
ot  saleabihty,  operation,  construction,  cost  of  manu- 
facture   and  so   forth.     This   results   in   forestalling 
many  of  the  difficulties  experienced  with  new  work 
Desirable  changes  of  design  for  the  purpose  of  cost 
reduction  are  brought  out,  and  the  product  designers 
have  the  advantage  of  the  intimate  experience  of  the 
duTtirn  *  ""^^  ^'''^'^'''^  ^"""^  operating  the  tools  of  pro- 
Standards    Drawings    and   Lists.-The    establish- 
rm^i  well-considered  standards  covering  the  de- 

Beve;^!^   "l??^'.l^^.J-z;^^^^^^^^^  PP'   ^^^5;   John   H.   Van 


f 


16 


THE  MECHANICAL  EQUIPMENT 


DRAFTING  DEPARTMENT 


17 


tails  of  design  of  the  product,  tools,  and  supplies  is 
of  incalculable  value  in  lowering  shop  costs  and  in- 
vestment in  shop  equipment. 

The  fourth  function  explains  itself  in  the  main. 
Drawings  for  complicated  work  should  be  accom- 
panied by  drawing  lists  locating  the  details  on  the 
various  sheets.  Such  lists  are  of  great  help  to  the 
assembling  department,  stores  department,  produc- 
tion, cost,  and  purchasing  departments.  Formerly 
the  compiling  of  bills  of  material  was  not  considered 
a  part  of  the  work  of  the  drafting  room,  but  this 
must  be  done  somewhere  in  the  plant  sooner  or  later, 
and  it  can  be  done  much  more  efficiently  and  ac- 
curately by  the  draftsmen  who  are  making  the  draw- 
ings. 

Record  of  Work  Done.— The  fifth  function— main- 
taining a  record  of  the  work  done — is  of  especial  im- 
portance in  connection  with  repair  wdrk  in  a  firm 
** building"  machinery.  Prior  to  1880,  drawings  were 
considered  only  as  instructions  for  the  production  of 
the  work.  They  were  made  on  paper,  usually  in 
pencil,  and  sent  out  into  the  shop.  Their  rough  usage 
soon  made  them  almost  illegible  and  anyone  who  has 
had  anything  to  do  with  repair  work  in  an  old  firm 
knows  how  nearly  useless  these  old  drawings  are  as 
a  record  of  what  was  originally  sent  out. 

With  the  advent  of  tracing  cloth  and  the  art  of 
blueprinting,  it  was  no  longer  necessary  to  send  the 
original  drawings  into  the  shop;  and  the  drawings 
became  much  fuller  in  their  information,  were  more 
carefully  studied  out,  and  became  complete  enough  to 
furnish   a   record   of   the   work   done.    This   entails 


several  things:  the  first  and  most  obvious  is  that  the 
work  and  the  drawings  should  conform,  but  only 
constant  watchfulness  will  accomplish  this,  for  there 
is  always  a  tendency  to  maKe  minor  changes  in  the 
shop  without  having  them  properly  recorded  on  the 
drawings.  It  is  important  that  the  work  should  fol- 
low the  drawing  exactly  or,  if  minor  changes  are 
necessary,  that  they  should  be  noted  on  the  drawing 
so  that  the  records  will  be  correct. 

Estimating.— The  sixth  function— estimating— de- 
pends largely  upon  the  nature  of  the  business. 
Where  the  prices  to  be  quoted,  as  in  the  case  of  large 
work,  are  dependent  upon  the  designs  submitted,  it  is 
evident  that  the  drawing  room  is  involved.  The  de- 
gree to  which  it  is  involved  and  the  manner  of  hand- 
ling the  work  varies  widely  and  cannot  be  outlined 
here.  In  some  cases  a  committee,  similar  to  the 
design  committee  already  referred  to,  can  be  of  great 
help  in  this  work. 

Supplementary  Punctions.- As  indicated  in  the 
schedule,  the  work  of  the  drawing  room  includes  the 
issuing,  indexing,  and  filing  of  blueprints,  sketches, 
data-sheets,  estimates,  and  other  lesser  items.  The 
issuing  must  be  done  in  an  orderly  manner  to  avoid 
leakage  of  information,  and  an  accurate  record  must 
be  kept  to  enable  the  recall  of  outstanding  prints 
Blueprints  floating  around  the  shop  unknown  to  the 
drawing  room,  which  are  not  recalled  for  alterations, 
are  a  fruitful  source  of  trouble. 

In  order  to  provide  ready  access  to  the  drawings 
and  needed  information,  the  drafting  department 
Should  maintain  indexes  for  all   of  the   following- 


AV 


!    J 


18 


THE  MECHANICAL  EQUIPMENT 


DRAFTING  DEPARTMENT 


19 


Drawings,  sketches,  data-sheets,  estimates,  orders,  is- 
sues of  prints,  etc.,  alterations,  and  sometimes,  but 
not  usually,  tools  and  patterns.  This  work  will  be 
taken  up  more  in  detail  later.  Proper  facilities  should 
be  provided  for  the  filing  of  all  drawings  and  records 
where  they  will  be  protected  from  loss  or  fire  and  will 
be  readily  accessible.  The  functions  of  issuing,  index- 
ing, filing,  and  recording  are  closely  related,  and  much 
of  the  efficiency  of  a  drawing  room  depends  upon  the 
business-like  way  in  which  it  is  carried  on. 

Personnel. — In  a  large  drawing  department  there 
will  be  a  chief  engineer,  a  chief  draftsman,  and  assist- 
ants, estimators,  designers,  detailers,  checkers,  tracers, 
blueprinters,  and  clerks  who  care  for  drawings,  blue- 
prints, orders  and  estimates.  In  small  drawing  rooms, 
two  or  more  of  these  positions  may  be  combined. 

The  head  of  the  drafting  room  should  be  relieved  as 
much  as  possible  of  routine  work.  He  should  have 
time  to  confer  with  the  sales  department,  to  plan 
new  work,  to  supervise  the  activities  of  the  drawing 
room,  and  he  should  also  be  free  to  spend  consider- 
able time  out  in  the  plant  following  work  in  progress. 
To  tie  him  down  too  closely  to  executive  routine  is  a 
serious  mistake.  He  should  be  a  man  of  high  order 
and  adequate  technical  training,  and  have  an  inti- 
mate knowledge  of  the  machinery  used  in  the  plant 
as  well  as  of  foundry  and  machine  shop  methods. 
His  assistants  mav  be  executives  who  relieve  him  of 
most  of  the  detail,  or  specialists  in  certain  fields  in 
charge  of  various  phases  of  the  work,  such  as  product, 
tools,  etc.,  with  designers  working  under  their  im- 
mediate supervision. 


Draftsmen  and  detailers  are  always  a  problem  in 
the  drawing  room.     It  is  difficult  to  keep  ambitious 
young  men  permanently  at  this  work.    College-trained 
men  learn  rapidly,  but  are  apt  to  be  deficient  in  prac- 
tical information;  and  if  they  are  good  they  soon  want 
to  move  on  to  other  work.    In  general,  shop-trained 
men,  who  have  partially  educated  themselves  through 
night  work,  etc.,  are  more  stable  and  often  more  satis- 
factory.   Some  plants  employ  women  for  tracing  and 
detailing.    They  are  admirably  adapted  for  this  work 
as  they  are  careful  and  accurate  and  willing  to  stay  * 
at  it.    The  typical  blueprint  boy  is  about  in  the  class 
of  the  printer's  devil,  and  a  good  one  is  a  treasure. 
Here,  too,  there  is  difficulty  in  keeping  a  good  boy  on 
the  job.    In  some  cases  this  has  been  settled  by  util- 
izing a  man  past  middle  life  who  is  glad  to  do  the 
work  and  will  not  be  a  rover.     The  problem  of  the 
clerical  force  in  the  drawing  room  differs  little  from 
the  same  problem  elsewhere. 

Policies.— First  and  foremost,  there  should  be  an 
open-minded  attitude  toward  ideas  from  any  source, 
whether  from  shop  and  foundry  foremen,  from  drafts- 
men, from  the  sales  organization,  or  from  competitors. 
A  good  chief  will  be  quick  to  recognize  and  utilize 
ideas  from  any  of  these  sources  and  will  be  generous 
in  acknowledging  the  credit  where  it  is  due.  A  jeal- 
ous or  small-minded  man  will  often  close  himself  from 
every  one  of  these  sources  of  information  and  in  so 
domg  will  limit  his  own  capacity  and  earning  power; 
m  keeping  them  open  and  in  acknowledging  credit 
where  it  is  due,  he  will  invariably  strengthen  his  own 
usefulness. 


// 


I 


20 


THE  MECHANICAL  EQUIPMENT 


DRAFTING  DEPARTMENT 


Patience  and  tact  are  closely  allied  with  this.  Fric- 
tion is  almost  always  latent,  at  least,  between  the  shop 
and  the  drawing  room.    Human  nature  is  such  that 
the  first  recourse  of  the  shop  is  to  lay  bad  work  at 
the   door   of   the   drawing   room.     Unless    carefully 
guarded  against  this  is  almost  certain  to  bring  about 
poor  team  play  which  will  eventually  run  into  steady 
losses   for   the   company.     For   example,    one   chief 
draftsman  whom  I  knew  was  a  good  designer  and  a 
good  executive  so  far  as  his  own  department  was  con- 
cerned, but  in  his  relations  with  the  shop  men  he  be- 
came so  overbearing  that  they  would  go  out  of  their 
way  to  put  him  in  a  hole.    When  a  drafting-room  mis- 
take was  discovered  in  the  shop,  they  would  say  noth- 
ing and  machine  the  work  exactly  as  drawn,  in  order  to 
allow  it  to  run  into  as  much  money  as  possible,  know- 
ing that  the  expense  would  be  charged  against  an  ac- 
count covering  bad  work  due  to  mistakes  in  design. 
A  new  chief  draftsman,  however,  who  was  a  man  of 
tact  and  familiar  with  this  situation  remedied  it  com- 
pletely. He  was  friendly  with  the  shop  men  and  his 
first  act  was  to  go  to  the  various  foremen  and  remind 
them  that,  while  it  was  an  interesting  game,  the  firm 
was  footing  the  bills.    He  agreed  that  when  he  found 
mistakes  on  the  shop  he  would  first  take  up  the  mat- 
ter directly  with   the   foremen,   and   they,   in   turn, 
agreed  to  report  any  errors  in  the  drawings  to  him  at 
once.     This  new  man  was  less  experienced  than  the 
first  and  no  better  designer,  and  yet  the  amount  of 
bad  work  due  to  mistakes  in  the  drawing  room  fell 
to  almost  nothing.    The  foreman,  who  usually  caught 
these  mistakes  just  as  the  work  was  starting,  would 


21 


tuck  the  blueprint  under  his  arm,  trudge  up  to  the 
drawing  room  and  the  trouble  would  be  made  right 
with  a  few  changes  on  the  drawing  at  the  expense  of 
some  ''jollying''  from  the  foreman  and  a  cigar  from 
the  chief  draftsman's  desk.  Probably  just  as  many, 
or  more,  mistakes  were  made  under  the  new  regime 
as  under  the  old,  but  they  were  caught  early  and  not 
allowed  to  run  into  money. 

I  have  already  stated  that  the  processes  of  manu- 
facture and  the  keeping  down  of  pattern  and  tool  ex- 
pense should  always  be  borne  in  mind.  They  should 
be  impressed  on  every  man  in  the  drafting  room.  The 
draftsmen  should  be  encouraged  to  spend  their  noon 
hours  and  such  other  time  as  may  be  available  in 
following  their  work  through  the  shop,  not  only  for 
the  educative  effect  upon  themselves,  but  also  because 
they  will  be  able  sometimes  to  catch  things  which  are 
going  wrong  on  work  with  which  they  are  familiar. 

Another  important  policy  in  drawing-room  practice 
should  be  the  determination  of  and  adherence  to 
standards.  There  seems  to  be  some  inherent  quality 
in  human  nature  which  tempts  men  to  depart  from 
standards  on  the  slightest  excuse,  especially  in  small 
details,  and  unless  watched  continually  the  number  of 
hand-wheels,  gears,  and  other  units  creeps  up— and 
with  it  shop  expense. 

There  should  be  a  systematic  use  of  experience  to 
preclude  unnecessary  repetition  of  work.  Hardly  a 
machine  or  class  of  machines  exists  in  which  certain 
units  do  not  recur  again  and  again.  Unless  prevented, 
these  units  are  re-designed  continually,  according  to 
the  whim  or  inspiration  of  the  moment;  and  the  re- 


22 


THE  MECHANICAL  EQUIPMENT 


suit  is  a  variety  of  patterns,  castings,  and  tools  which 
could  be  greatly  reduced  by  forethought  and  stand- 
ardization. The  advantages  of  studying  these  units 
as  a  class  are  that  interchangeability  is  increased;  in- 
vestment in  patterns,  castings,  and  tools  is  minimized; 
assembling  work  is  facilitated,  and  quicker  deliveries 
are  made  possible.*  This  work  may  take  the  form  of 
data-sheets  covering  standard  details  of  design,  stand- 
ard tools,  and  methods  of  manufacture  which  will  be 
available  for  the  entire  drafting  room  and  for  subse- 
quent work. 

The  work  of  the  department  should  be  planned  out 
and  scheduled  ahead  as  far  as  possible.  Bulletin 
boards,  similar  to  those  in  a  modern  planning  depart- 
ment, covering  work  in  hand,  work  ready  to  take  up, 
and  work  ahead,  are  perfectly  applicable  to  the  draft- 
ing room.  In  fact,  they  can  be  applied  there  with  as 
great  advantage  and  with  very  much  less  trouble  than 
in  any  other  part  of  the  plant. 

All  calculations  and  sketches  should  be  kept.  Many 
drafting  rooms  do  not  allow  the  use  of  pads  or  loose 
pieces  of  paper  but  issue  numbered  books  to  the 
draftsmen  in  which  they  do  all  such  work.  These 
books  are  useful  in  checking  mistakes  in  design,  and 
are  the  best  kind  of  evidence  in  patent  litigation. 

As  soon  as  a  drafting  room  reaches  any  size,  the 
principle  of  the  division  of  labor  should*^  be  intro- 
duced, and  the  work  of  detailing  and  tracing  separ- 
ated from  that  of  designing.  This  keeps  the  highly 
paid  men   on  the   skilled  work.     Only  the  highest 

♦See  "Machine  Shop  IManagement,"  pp.  20-27;  John  H.  Van  De- 
venter.    McGraw-Hill  Book  Co. 


DRAFTING  DEPARTMENT 


23 


standard  of  what  constitutes  a  working  drawing 
should  be  tolerated.  It  should  give  complete  instruc- 
tions from  the  designer  to  the  workman — there  is  no 
middle  ground.  It  should  be  positive,  thoroughly 
definite,  clear,  and  self-sufficient. 

Practice. — The  practice  of  the  drawing  room  as  to 
sizes  of  drawings,  style  of  dimensioning,  sectioning, 
etc.,  should  be  standardized  and,  in  the  form  of  data- 
sheets, put  into  the  hands  of  every  draftsman  and 
tracer  when  he  enters  the  drawing  room,  and  strict 
adherence  to  the  standards  should  be  required.  Var- 
ious codes  of  practice  have  been  published,  one  of 
which  has  been  prepared  by  the  American  Society  of 
Mechanical  Engineers.* 

There  is  an  increasing  tendency  in  making  detail 
drawings  to  show  only  one  piece  on  each  sheet.  This 
is  highly  commendable,  for  it  facilitates  work  in  the 
order  and  production  departments  and  also  in  the 
shop.  It  can  be  carried  too  far,  however,  but  should 
be  considered  and  the  principle  adopted  as  far  as  feas- 
ible. Many  drawing  rooms  specify  the  limits  of  ac- 
curacy, style  of  finish,  allowance  for  finish  on  pat- 
terns, and  so  on.  This,  too,  can  be  carried  to  ex- 
tremes, but  the  practice  is  sound  and  should  be  given 
careful  attention. 

For  convenience  in  filing,  a  standard  location  and 
style  of  title  should  be  insisted  upon;  and  the  infor- 
mation contained  in  the  title  should  conform  in  size 
and  emphasis  to  its  relative  importance.    If  the  filing 

♦"Machinery's  Reference  Series,"  Numbers  2  and  33,  give  a  very 
rnnm^^.rl-^"^^?^^'?"^  ^"^  ''"'^•^  Covering  many  points  in  drawing 
S^  akn  VnnV''  l"""^  to  include  here  but  well  worth  consulting 
fcee  also  \an  Deventer;    "Machine  Shop  Management."  Section  II 


24 


THE  MECHANICAL  EQUIPMENT 


system  is  based  on  numbers,  the  number  should  be 
most  conspicuous.  A  title  should  contain  the  follow- 
ing information: 

Name  of  Company. 
Name  of  machine. 
Name  of  parts  shown. 
Number  of  drawing. 

Number  of   order First  used  for 

Scale. 

Designed  by Date 

Traced   by **   

Checked  by '*   

Approved  by **   


Tools  Available.— Lists  of  tools  available  for  work, 
with  such  dimensions  as  concern  the  drafting  room, 
(such  as  ranges  of  sizes,  etc.)  and  lists  of  standard 
screws,  bolts,  and  other  supplies,  may  be  included  in 
the  data-sheets  already  referred  to  and  are  a  great 
help  in  standardizing  the  shop  practice. 

Checking. — It  is  often  desirable  that  all  designs 
should  be  checked  twice;  once  before  the  drawing  is 
traced  to  discover  any  mistakes  in  design,  and  again 
after  the  tracing  is  finished  to  make  sure  that  dimen- 
sions and  other  details  are  correctly  copied.  Many 
firms,  however,  check  their  work  only  once — after  the 
tracing  has  been  completed.  In  either  case  it  should 
be  done  in  a  systematic  way  and  the  drawing  exam- 
ined for: 

1.  General  design,  strength,  material,  method  of  manu- 

facture. 

2.  Dimensions; — their  accuracy,  sufficiency  and  arrange- 

ment 


DRAFTING  DEPARTMENT  25 

3.  Finish  and  finish  marks. 

4.  Patterns  and  pattern  numbers. 

5.  Molding  and  foundry  work. 

6.  Comparison  with  bill  of  materials. 

7.  Comparison  with  list  of  stock  parts,  tools,  etc. 

8.  Notes. 

Blueprints. — Blueprints  should  be  issued  only  with 
the  shop  orders  or  upon  signed  requisitions  from  the 
proper  persons,  and  record  should  be  made  of  each 
issuance,  giving  date  and  to  whom  issued.  This  rec- 
ord is  necessary  for  the  recall  of  prints  in  making 
alterations.  Prints  that  are  standard  and  subjected 
to  considerable  use  should  be  mounted  on  heavy  card- 
board, or  other  material,  and  varnished  or  made 
waterproof.  In  some  cases  it  is  desirable  to  bind  sets 
of  prints  together  into  books  for  use  in  assembling 
and  erecting. 

Filing.— Generally,  drawings  and  tracings  are  filed 
in  flat  drawers  which  preferably  are  made  of  sheet 
metal  and  located  in  a  fireproof  vault  opening  into 
the  drawing  room.  Rolling  the  tracings  and  draw- 
ings cannot  be  too  greatly  condemned,  for  it  is  diffi- 
cult to  find  the  right  roll  and  they  are  troublesome 
to  use  when  unrolled.  If  possible  only  one  size  of 
drawing  should  be  filed  in  one  drawer.  When  large 
and  small  drawings  are  filed  together  indiscrimi- 
nately, the  small  ones  are  difficult  to  find  as  they  are 
apt  to  get  into  the  back  of  the  drawer  and  sometimes 
get  lost  behind  it.  A  guard  across  the  top  at  the 
back  of  the  drawer  is  a  help  in  lessening  this  last 
trouble. 


IV 


26 


THE  MECHANICAL  EQUIPMENT 


DEAFTING  DEPARTMENT 


27 


If 


Changes  and  Alterations.— No  deviation  from  the 
drawings  should  be  allowed  without  formal  authoriza- 
tion from  the  drawing  room.  This  is  absolutely  es- 
sential for  the  maintenance  of  an  accurate  record  of 
work  done.  If  any  changes  or  improvements  are 
made,  the  drawing  room  should  recall  outstanding 
prints  and  substitute  new  or  corrected  ones.  Eecord 
should  be  made,  either  upon  the  drawing  itself  or 
elsewhere,  of  the  serial  numbers  of  the  machines  for 
which  the  drawing  was  used,  the  date  when  it  ceased 
to  be  standard,  the  drawing  by  which  it  was  super- 
seded, and  the  first  machine  on  which  the  new  draw- 
ing was  used.  This  record  is  invaluable  in  caring 
for  repairs.* 

In  making  changes  and  alterations,  it  is  well  to  fol- 
low a  definite  procedure  to  make  sure  of  covering  the 
various  items  which  require  attention.  The  follow- 
ing list  covers  most  of  them: 

1.  General  assembly  tracings. 

2.  Detail  tracings. 

3.  Drawing  lists. 

4.  All  blueprints  outstanding  should  be  recalled  and  re- 

placed with  correct  ones. 

5.  Patterns  involved. 

6.  Special  tools  involved. 

7.  Disposition  of  stock  on  hand,  if  any. 

8.  Necessary  records  of  the  change. 

Equipment.— The  general  practice  in  the  past  has 
been  to  use  drawing  tables  large  enough  for  a  loose 

♦For  procedure  in  changes  in  alterations,  see  Van  Deventer, 
"Machine  Shop  Management,"  pp.  35-37;  also  "Machinery  Reference 
Series,"  Nos.  2  and  33. 


drawing  board,  with  room  at  the  side  for  reference 
drawings  and  other  papers.  In  many  places  the  verti- 
cal board  is  preferred  and  for  large  drawings  it  is 
unquestionably  more  convenient,  but  when  it  is  used 
tables  should  be  provided  for  holding  any  reference 
drawings.  In  either  case  parallel  rulers  will  be  found 
preferable  to  T-squares;  in  large  work  their  use  is 
almost  universal.  The  **Universar'  drafting  ma- 
chine," combining  a  parallel  motion,  protractor,  and 
scales,  is  a  convenient  and  time-saving  device,  well 
adapted  to  many  forms  of  drafting  work. 

Few  modern  drafting  rooms  rely  upon  sun  print- 
ing for  making  their  blueprints.  A  number  of 
electric  machines  are  on  the  market  which  make 
prints  rapidly,  day  or  night,  rain  or  shine.  Many  of 
them^  combine  washing  and  even  drying  with  the 
printing  process,  and  their  convenience  and  avail- 
ability at  all  times  make  them  preferable  in  every 
way  to  the  old  sun-printing  frames  wherever  there  is 
any  large  amount  of  blueprinting  to  be  done.  Such  a 
machine  is  shown  in  Figure  3. 

Two  new  machines  are  now  available,  the  * 'Photo- 
stat''and  the  '^Eectigraph,"  which  will  photograph 
any  kmd  of  record— a  drawing,  order,  printed  page- 
in  a  few  moments'  time  and  at  moderate  cost. 
While  the  machines  are  expensive,  they  can  be  used 
in  a  great  many  ways  for  saving  time  and  in  avoid- 
ing errors  in  copying.  Their  possibilities  and  avail- 
ability  should  be  considered  in  every  large  drafting 
room.  ^ 

Location  of  the  Drafting  Room.— Generally  speak- 
ing, the  drafting  room  should  be  convenient  to  the 


DRAFTING  DEPARTMENT  29 

office,  pattern  shop,  tool  room,  and,  if  possible,  cen- 
trally located  with  respect  to  the  shop.    It  should  be 
roomy,  well  ventilated,  and  have  white  or  light-toned 
wal  s.    The  best  possible  lighting  is  the  cheapest-a 
north  hght  for  the  daytime,  and  an  artificial  light 
I  so  arranged  as  to  avoid  eye  strain  and   eliminate 
.shadows  for  evening  work.    The  work  calls  for  close 
use  of  the  eyes,  and  few  realize  the  lowering  of  eT 
ciency  m  a  drafting  room  where  the  light  is  ooor 
The  expenditure  represented  by  the  difference   be 
t^^^^  lighting  and  the  best  obtainaMet 

L,.;^^"-^"  =    "*'"''"'■•''   f-'shtlng."   Chap.   VI.   on   Drafting  Room 


KG.    3.      CONTINUOUS    ELECTRIC    BLUE    PRINTING    MACHINE 

C.  F.  Pease  Company. 

28 


/ 


DKAFTING  DEPARTMENT  2!» 

office,  pattern  shop,  tool  room,  and,  if  possible,  cen- 
trally locate,]  with  respect  to  the  shop.     It  should  he 
n.on,y,  well  ve„tilate<l,  an,l  have  white  or  li«ht-toned 
«=.l  s.      Ihe    .est  possible  lighting-  is  the  cheapest-a 
north   light  for  the  <layti,ne,  an<l   an  artificial   li.-ht 
so   arranged   as   to   avoid    eye   strain    an,l    eliminate 
shadows  tor  evening  work.     The  work  calls  for  close 
»:-■  "I  <li<'  eyes,  a.,,1  few  realize  th,.  lowring  of  efti- 
;•;<•->•   in  a  drariing  room   when-  the  light  T.  poor 
llH.   expen.l,(,ne    represented    by    ,he   difference    be-' 

"cen  (he  poorest  lighting  and  the  best  obtainable    s 
''^oon  [)ai(l  lor."  ^luauii   ks 


*n..\v('ll:     -Fju-tory    M-htIn-"    CJiMn     vt        .    r. 


ftin^'    n«K»ni 


FIG.    3.      CONTINUOT^S    P:T.ECTRIC    BLri:     I'RINTIMJ     MACHINE 

('.   F.  Tease  Company. 

28 


11 


I 


CHAPTER  III 
THE  PATTEEN  SHOP 

Function  and  Location. — The  functions  of  the  pat- 
tern shop  are  to  make,  maintain,  and  store  patterns 
and  core  boxes,  and  to  keep  the  pattern  records.  As 
patterns  are  usually  of  wood,  this  involves  a  wood- 
working shop  with  the  necessary  benches  and  ma- 
chinery. Metal  patterns  may  be  used  in  manufac- 
turing plants  where  there  is  repetition  work  and 
machine  molding;  and  this  would  involve,  in  addi- 
tion, metal  working  equipment  adapted  to  the  manu- 
facture of  iron  patterns,  stripping  plates,  and  such 
articles.  The  pattern  shop  is  in  frequent  com- 
munication with  the  foundry  and  with  the  drafting 
room.  It  should  be  located,  therefore,  conveniently 
with  respect  to  these  two  departments,  preferably 
between  the  two. 

Balance  of  Pattern  Makers*  and  Molders'  Time. 
— The  cost  of  a  pattern  is  distributed  over  all  the 
castings  made  from  it,  and  when  great  numbers  of 
castings  are  made,  may  become  almost  negligible;  but 
the  molder's  time  enters  into  the  cost  of  every  mold 
and  increases  directly  with  the  number  of  molds 
made.  If  but  one  casting  is  wanted,  it  pays  to  make 
the  cheapest  pattern  possible  and  let  the  molder 
spend  more  time  on  his  work.  Where  the  pattern  is 
to  be  used  for  many  castings,  it  will  pay  to  spend 
much  more  time  upon  it,  if  thereby  the  molding  cost 

30 


PATTERN  SHOP  31 

can  be  cut  down,  for  this  saving  will  appear  in  every 
casting  made.  For  illustration,  let  us  assume  the 
pattern  maker's  *and  molder's  time  each  at  $4  per 
day,  and  compare  the  total  cost  in  making  one  cast- 
ing as  against  ten  castings. 

One  casting  Ten  castings 

Pattern  maker's  time,  1  day $4.00  $4.00 

Molder's  time,  1/2  day  to  each  casting.     2.00  20.00 

Total  combined  cost $6.00  $24.00 

Combined  cost  per  casting 6.00  2.40 

Suppose  now  the  pattern  maker  to  spend  three  days 
making  a  better  type  of  pattern  which  will  enable  the 
molder  to  make  molds  at  the  rate  of  ten  per  day. 
We  then  have: 

T^  ,,  ,      ,      .  One  casting  Ten  castings 

Pattern  maker's  time,  3  days $12.00  $12.00 

Molder's  time,  1-10  day  to  each  cast- 
I'^S   40  4.00 

Total  combined  cost .$12.40  $16.00 

Combined  cost  per  casting 12.40  1.60 

A  comparison  of  the  first  columns  shows  clearly 
that  for  one  casting  it  will  pay  to  make  a  cheap  pat- 
tern and  let  the  molder  spend  a  half  day  on  the 
mold.  For  ten  castings  it  will  be  cheaper  to  let  the 
pattern  maker  spend  several  days  in  making  a  better 
pattern  to  gain  the  saving  in  the  molder's  time.  If 
similar  calculations  are  made  on  the  basis  of  two, 
three,  and  four  castings,  it  will  be  found  that  the 
cheap  pattern  is  still  the  more  economical.  At  five 
castings  the  combined  cost  per  casting  is  the  same, 
i^eyond  that  number  the  advantage  is  increasingly  in 
tavor  of  the  more  expensive  type  of  pattern. 


^^ 


32 


THE  MECHANICAL  EQUIPMENT 


In  the  above  example,  both  the  wage  rates  and  the 
molder's  and  pattern  maker's  time  have  been  assumed 
arbitrarily,  but  the  principle  is  the  same  in  any  case. 
Each  pattern  is  a  separate  problem.  Sometimes  the 
simplest,  at  other  times  the  most  expensive,  type  will 
be  cheapest.  From  this  principle  it  is  obvious  that 
there  should  be  constant  and  closest  co-operation  be- 
tween foundry  and  pattern-shop  foremen  to  determine 
the  kind  of  patterns  to  be  made. 

The  pattern  shop  and  the  drawing  room  must  also 
work  together  to  utilize  existing  patterns  as  far  as 
possible  and  to  reduce  the  number  of  patterns  by  the 
use  of  loose  pieces  for  making  right-  and  left-hand 
castings,  etc. 

The  facilities  for  storing  patterns  should  be  ade- 
quate, accessible,  fireproof,  and  capable  of  expansion. 
All  patterns  should  be  indexed  and  records  kept  show- 
ing their  location,  condition,  etc. 

Pattern  making  constitutes  a  highly  skilled  trade 
and  is  too  intricate  to  be  dealt  with  in  detail  here. 
Those  who  would  desire  even  a  general  knowledge  of 
it  are  referred  to  some  of  the  elementary  books  on 
the  subject.  Here,  as  in  the  case  of  the  drafting 
room,  we  will  take  up  only  some  of  the  general  fea- 
tures. 

Types  of  Patterns. — The  simplest  form  of  pattern 
is  the  one-piece  pattern  used  only  for  small  castings. 
Its  sole  merit  is  that  of  being  cheap.  It  throws  a 
great  deal  of  work  on  the  molder,  but  it  is  often 
used  for  simple  work  where  only  one  casting  or  but 
a  few  castings  are  required. 

Where  castings  are  required  in  moderate  number.'. 


PATTERN  SHOP 


33 


the  pattern  would  be  split,  and  the  two  portions  dow- 
eled together,  one  half  forming  the  drag  impression, 
the  other  the  cope.*  This  simplifies  the  work 
of  molding,  and,  hence,  this  type  is  most  commonly 
employed  for  medium  sized  work.  The  parting  of  the 
mold  generally  coincides  with  the  parting  of  the  pat- 
tern. After  the  mold  is  formed,  the  cope  is  lifted  off 
the  drag,  the  two  halves  of  the  pattern  removed  and 
put  together  again  for  use  on  the  next  mold. 

When  the  principal  surfaces  of  a  casting  are  plane 
surfaces  or  those  of  translation,  a  skeleton  pattern  is 
used  which  gives  only  the  outline  of  the  casting.  This 
is  set  m  the  mold,  and  straight-edges  or  -strike 
boards  are  slid  along  the  skeleton  to  generate  the  * 
mtermediate  surfaces.  This  type  is  very  useful  for 
large  work,  as  the  saving  in  the  cost  of  pattern  work 

rpSff'^"""  K""'^^^  "^^^  ^'  ^PP^^^^  t^  surfaces  of 
revolution    such  as  cylinders,  wheels,  gears,  and  so 

bLpi.f  ^    •    ^^^'"^  ^^'  ""^^^^^  ^^  the  surface  to 
be  generated  is  mounted  at  the  desired  radius  upon 

an  arm  swinging  on  a  spindle  and  used  to  generate 

IteTs   :"  "'  ''!  "^^'-    '"  "^^^^^  -^1^«  f-"ea 

n  a  s;i;Hl'''T''  ^f'*''^  '^  ^"^  t^^th  i«  -counted 
on  a  spmdle  and  revolved  at  the  proper  pitch  radius 

^om  position  to  position.    This  principle  i's  embodle^^ 
inf  n^LY     ^^^^^^^  ''""'''^  ^"  th^  Mesta  mold- 

mli    of  IT^r  "''  ™^^'^  '  ^^^^^^  -i"^  a  seg- 
ment of  the  pattern  carrying  the  tooth  is  mounted 

For  definitions  of  drag  and  cope,  see  Chapter  V.  page  56. 


Ill 


'< 


34 


THE  MECHANICAL  EQUIPMENT 


on  a  cross  rail,  and  the  mold  revolves  under  it  from 
position  to  position  until  all  the  teeth  are  molded.  In 
this  way  a  very  accurate  mold  may  be  made.  In 
sweeps,  the  strike  board  may  also  be  made  to  ad- 
vance uniformly  along  the  axis  as  it  is  rotated.  This 
generates  a  spiral  surface  and  is  used  for  molding 
the  spiral  grooves  in  rope  sheaves  and  sometimes  for 
the  working  faces  of  screw  propellers. 

Gated  Patterns. — ^Where  small  castings  are  made  in 
great  quantity,  it  is  best  to  make  several  impressions 
in  one  mold.  This  involves  the  use  of  gated  pat- 
terns,— the  patterns  for  a  number  of  pieces  being 
mounted  upon  a  single  plate  and  molded  simultane- 
ously. The  patterns  are  connected  by  a  common  gate 
which  leads  the  molten  metal  from  a  single  pouring 
opening  to  the  various  impressions.  Gated  patterns, 
which  are  very  generally  used  on  molding  machines, 
may  be  made  of  wood,  but  they  are  more  often  made 
of  cast  iron  or  brass.  Two  general  types  of  gated  ma- 
chine patterns  are  used:  in  the  first,  the  patterns 
are  permanently  secured  to  the  pattern  plate;  the 
flask  is  placed  over  the  pattern,  filled  with  facing  and 
sand  which  is  rammed,  squeezed,  or  jarred,  and  the 
mold  is  then  lifted  clear  of  the  patterns.  In  the  sec- 
ond—  the  stripping-plate  type  —  the  patterns  are 
mounted  on  a  separate  plate.  After  the  mold  is  made, 
the  patterns  are  withdrawn  downward  clear  of  the 
mold  through  a  ** stripping  plate"  which  fits  the  pat- 
terns closely  at  the  parting  line  and  supports  the  sand 
during  the  act  of  withdrawal.  This  type  requires 
little  or  no  draft,  and  the  molding  work  is  fast. 
Where  cope  and  drag  impressions  are  necessary,  it  is 


[ 


r No  Finish  ^f^rfing  L/ne 


'inish 
and-' 
Draft: 


Finish- 


6ond .: 


'Draft :'' 

and  Finish 

^'•Finish  :\ 

Profty'.'^'ff'^^pir-^^i^r ............ 

but  no  finish;:  "^Sec/ion  of /rn/sheaf':':. 

■  ■•:■::'■■::.■■.'■/■■:■::.■■.  /Vece ■.-.■'  ^ :•'■!■ 

SOLID  PATTERN- SET  IN  THE  DRAG 
SHOWING  VARIOUS  ALLOWANCES 


Co/?e   '-{f-fnish  and  Draff. ::^'n'sh  on/t/.-  :  rSand':  y-'\ 

■■^^^■^>^-~^''Dii,ffS:^fiL^^^ 


•  •  •;./■> 

■  Drdq^<:,z:-^-Dow^l.  '.*. 
'\HaJfyy.yr:}::Pin-: 


SPLIT    PATTERN 


SECTION   X-X 

Parfinq  line'    =:';"-!'i  •.••;•:  '.••••:••  ••.•.•;.•..•.■ 

of  Mo/a:::  .■:■>:■:  ^^:^.•: :  :--;;;-V;- •^;^! 

i: .  oano/'Cojfe'::\      |  •  -.  •:■•.■ 

:■  ;.  ■•;."t H;  ■.'■  •;  "■■  igg  fe  }.  ■  v^     f^;  ■:•}}. 

.■.'•.••"■•.  ijrrrf: -Core /?/-//>/;''; vTT^*;'.*;:" 
':•  '..'•. ■.'.•.■'•■•■": '.: Sand'Draa-  '•:'■  '•'■'.':'. '•: 


rrri. 

"1  i      !  I  ^"^ggg  fo  be  cast 


WG.  4.      TYPES  OF  PATTERNS 
35 


36 


THE  MECHANICAL  EQUIPMENT 


desirable  to  arrange  them  on  the  same  pattern  plate 
on  opposite  sides  of  a  line  of  symmetry,  a  cope  im- 
pression on  one  half  matching  a  drag  impression  on 
the  other  half.  If  this  is  done,  the  cope  and  drag 
of  the  mold  will  be  the  same.  This  saves  making 
two  plates,  one  for  cope  and  one  for  drag  impres- 
sions, and  lessens  the  amount  of  work  in  both  pat- 
tern shop  and  molding  floor.  Figure  4  shows  a  sim- 
ple gated  pattern,  not  mounted  on  a  plate.  The  prin- 
ciple, however,  is  the  same  as  that  just  described. 

Patterns  for  large  work,  such  as  that  done  in  loam 
foundries,  are  built  up  of  many  pieces  and  are  often 
very  complicated.  Parts  of  the  pattern— for  in- 
stance, large  flat  surfaces— may  be  left  open  and  the 
mold  finished  with  a  strike  board;  while  flanges, 
bosses,  etc.,  may  be  made  in  full  and  carried  on  the 
frame  of  the  pattern.  Arms  and  other  projections 
may  be  in  loose  pieces,  and  the  mold  may  be  made  in 
flasks  having  two  or  even  more  parting  lines. 

Pattern  Material.— The  prevailing  material  for  pat- 
terns is  wood— air  seasoned  and  perfectly  dry.  Pat- 
terns of  a  permanent  nature  and  of  fair  size  should 
be  built  up  of  several  thicknesses,  with  the  grain  re- 
versed to  neutralize  the  tendency  to  warp.  White 
pine  is  most  generally  used  as  it  is  straight  grained,  is 
free  from  knots,  works  easily,  and  takes  varnish  well. 
For  molding  large  quantities  of  small  castings  mahog- 
any is  used.  It  is  much  stronger  and  harder  than 
pine,  works  less  easily,  but  it  stands  moisture  as  well 
or  better,  and  has  little  tendency  to  warp.  Bay  wood, 
a  species  of  mahogany,   but  lighter  and  softer,  is 


PATTERN  SHOP 


37 


sometimes  used,   and,   for  special  purposes,   cherry, 
black  walnut,  maple,  and  birch. 

AUowances.— Certain  allowances  are  made  in  pat- 
terns that  give  them  a  shape  slightly  different  from 
the  casting  to   be  produced   from   them.     Foundry 
metals  shrink  in  cooling,  and  if  castings  are  desired 
of  a  certain  size,  the  patterns  must  be  made  larger 
by  an  amount  sufficient  to  allow  for  this  shrinkage 
The  allowance  for  grey  iron  is  about  an  eighth  of  an 
inch  to  a  foot;  for  malleable  iron  and  brass,  about 
three-sixteenths  inch  to  a  foot,  and  for  cast  steel  and 
aluminum,  which  have  a  heavy  shrinkage,  as  high  as 
one-fourth  inch  to  a  foot.    For  various  reasons  this 
shrinkage  is  not  always  equal  in  all  directions  and 
this  discrepancy  must  be  cared  for  by  varying  the 
shrinkage  allowance. 

Another  allowance  which  must  be  made  in  patterns 
IS  that  for  draft.  It  is  practically  impossible  to  lift 
the  pattern  from  the  mold  without  breaking  the  cor- 
ners if  the  sides  of  the  pattern  are  at  right  angles 

1  1    rT.  f^  ^'^''     ^"  ^^"^^  *^i«'  *hey  are  made 
on  a  shght  taper  which  should  be  greater  on  an  in- 

FTgure'r         ^^^"^  ^""^  ^"  '''*'''^'  ^''''  ^'  '^^^^  i^ 

chZirr  *^'  T^"'  "^  ^^'  '^'^""^  ^''  to  be  ma- 
chined  there  must  be  additional  metal  added  which 

and  sLT"^  V"  ^^^^^"i"^  operations.  On  small 
and  simple  castings  this  may  be  as  little  as  1-16  inch, 
m  large  castings,  %  or  i/^  inch  must  be  allowed, 
they  arP  l^.^  P^^^^^^^/f  withdrawn  from  the  mold 
frn  T  ^^"^  ""^PP^^  by  *be  molder  to  free  them 
from  the  sand.    This  enlarges  the  mold  slightly  and 


38 


THE  MECHANICAL  EQUIPMENT 


PATTERN  SHOP 


39 


is  sometimes  taken  into  account  in  the  dimensions  of 
the  pattern.  Another  advantage  of  the  stripping- 
plate  type  of  pattern  is  that  it  does  away  with  the 
difficulties  introduced  by  rapping  as  well  as  the  ne- 
cessity for  draft,  which  was  previously  mentioned  on 

page  34. 

Waxping  and  Splitting.— The  principal  cause  of 
warping  in  patterns  is  moisture  in  the  wood.  For 
this  reason  the  lumber  used  should  be  thoroughly 
seasoned  and  the  pattern  may  be  built  up  as  already 
explained.  The  second  cause  of  warping  is  moisture 
in  the  mold.  To  provide  against  this,  patterns  are 
heavily  varnished  and  painted  to  keep  the  moisture 
put.  Splitting  is  usually  caused  by  rapping  the  pat- 
tern in  the  mold.  Suitable  rapping  plates  will  obviate 
trouble  from  this  source. 

Fillets.— All  corners  should  be  rounded  whenever 
possible.  The  corners  look  better,  the  pattern  makes 
a  cleaner  mold,  the  molten  metal  does  not  wash  away 
the  sand,  and  the  castings  are  much  stronger.  For 
internal  corners'  in  the  pattern  wood  strips  may  be 
used,  or  leather  strips— which  come  especially  cut  for 
this  purpose— can  be  secured  in  the  corner  with  tacks 
and  glue.  These  leather  strips  are  widely  used,  as 
they  can  be  run  around  curves  and  irregular  places. 
For  cheap  patterns  intended  for  temporary  use,  the 
fillets  may  be  made  of  linseed-oil  putty. 

Core  Prints.— The  supports  for  all  cores  should  be 
large  and  well  placed.  The  best  practice  in  modern 
shops  is  to  standardize  the  sizes  of  core  prints  wher- 
ever possible.  This  lessens  the  cost  both  in  the  pat- 
tern shop  and  in  the  core  room. 


Marking  and  Painting.— All  patterns  should  be 
painted,  preferably  in  two  colors— the  pattern  in 
black,  and  the  core  prints,  core  parts,  and  boxes 
in  red.  All  the  loose  pieces  of  both  the  patterns  and 
core  boxes  should  be  so  marked  as  to  identify  them 
with  the  pattern  to  which  they  belong. 

Pattern  Storage.— The  pattern  storage  should  be 
guarded  against  fire  with  the  greatest  care.  It  should 
be  so  located  that  it  may  not  be  in  danger  of 
catching  fire  from  sparks  from  the  foundry  or  from 
other  buildings;  and  it  should  be  protected  from  fire 
from  within  by  the  best  possible  fire-fighting  appa- 
ratus. Hydrants  and  hose  should  be  available  and,  if 
possible,  a  sprinkler  system.  The  air  should  be  kept 
warm  and  dry  to  avoid  the  splitting  and  warping  of 
the  patterns.  Obviously,  related  patterns  and  their 
parts  should  be  together.  The  patterns  should  not 
be  piled  at  random;  they  should  be  stored  according 
to  some  well-thought-out,  orderly  system,  with  the 
smaller  ones  on  shelves  arranged  in  aisles.  Shelves 
for  patterns  should  be  adjustable,  and  the  whole 
scheme  of  arrangement  capable  of  expansion,  as  the 
number  of  patterns  to  be  stored  increases  steadily 
and  may  become  very  great — some  pattern  storages 
in  this  country  house  more  than  a  million  patterns. 
Every  pattern  should  have  a  definite  place  and  should 
be  identified  with  that  place  in  the  pattern  index. 

Index  System. — A  card  index  should  >  cover  all  pat- 
terns in  storage,  and  each  card  should  contain  full 
information  necessary  to  locate  and  describe  the  pat- 
tern. On  each  card  the  following  data  should  be 
shown; 


I 


r  II 


i 


40  THE  MECHANICAL  EQUIPMENT 

Pattern  number 

Size  and  name  of  the  part 

Size  and  name  of  the  machine 

Drawing  number 

Order  number 

Date  made 

Location  in  loft,  section,  aisle,  and  shelf 

Number  of  pieces  in  pattern 

Number  of  pieces  in  core  box 

Record  of  alterations 

A  record  of  the  castings  made  from  pattern  and  the 
order  numbers  covering  them  may  be  given  in  suit- 
able space  on  the  backs  of  the  cards. 

Records. — Systematic  records,  usually  by  a  card 
index,  should  be  maintained  of  the  issuing  of  pat- 
terns, as  follows: 

Patterns  sent  to  foundry  and  core  room. 

Patterns  sent  to  outside  foundries. 

Patterns  sent  to  pattern  shop  for  repairs. 
In  some  storerooms  provision  is  made  for  cards  on 
the  shelves,  which  will  give  the  location  of  the  pat- 
terns when  they  are  out  of  storage.  This  is  not  al- 
ways necessary,  as  the  above  office  records  should 
contain  such  information. 


CHAPTER  IV 
FOUNDEY  METALS  AND  FOUNDEY  BUILDINGS 

Metals. — The  principal  metals  which  form  the  prod- 
uct of  foundries  are  grey  iron,  chilled  iron,  white  or 
malleable  iron,  cast  steel,  brass  and  bronze  alloys,  and 
aluminum. 

Grey  Iron.— Grey  iron  is  used  for  machinery  cast- 
ings. Its  ultimate  tensile  strength  will  run  from 
20,000  to  25,000  pounds  per  square  inch.  But  for  these 
castings,  soundness  and  ease  of  machining  are  of 
more  importance  than  great  strength.  A  great  many 
mixtures  of  grey  iron  are  used  for  special  purposes. 
The  chemical  composition  and  strength  are  more 
or  less  influenced  by  the  size  of  the  product,  and  spe- 
cial physical  properties  are  sometimes  required.  Cyl- 
inder and  pump  castings,  for  example,  should  be 
dense,  close  grained  and  free  from  shrinkage  spots, 
and  as  hard  as  is  consistent  with  machining  in  order 
to  wear  slowly  to  a  high  polish.  Castings  for  dynamo 
frames  are  made  of  very  soft  iron  to  prevent  the  re- 
tention of  residual  magnetism. 

Stoves,  radiators,  and  ornamental  castings,  on  the 
other  hand,  are  made  from  iron  with  high  percentages 
of  phosphorous  and  silicon.  This  composition  is  very 
fluid  in  the  molten  state,  flows  freely  in  thin  sections, 
and  fills  the  finest  lines  of  the  mold:  it  is  brittle  and 

41 


42 


THE  MECHANICAL  EQUIPMENT 


i 


will  not  machine  well,  but  these  castings  are  not  in- 
tended to  be  machined.  '^Semi-steeP'  is  made  by 
adding  from  10  to  40  per  cent  of  steel  scrap,  giving 
a  strong  iron  which  can  be  machined,  although  with 
some  difficulty.  Guij  iron  is  the  most  reliable  and 
highest  grade  of  grey  iron  made:  It  is  melted  in  air 
furnaces  and  used  for  small  engine  cylinders,  fine  fin- 
ishing rolls,  and  similar  precise  work. 

Chilled  Iron.— When  grey  iron  is  poured  and  al- 
lowed to  cool  slowly,  the  casting  is  soft  and  the  car- 
bon content  is  largely  in  the  free  or  graphitic  state. 
But  if,  instead,  the  pour  is  cooled  suddenly,  the  sur- 
face to  a  depth  of  one-half  inch  to  an  inch  becomes 
exceedingly  hard  and  crystalline,  and  the  carbon  re- 
mains chemically  combined  with  the  iron.    This  prop- 
erty is  utilized  in  the  making  of  chilled-iron  castings. 
In  making  the  castings  the  metal  is  poured  into  iron 
molds  or,  more  generally,  into  sand  molds  in  which 
iron  castings  covering  the  part  to  be  hardened  have 
been  set.     The  metal  pieces  used  for  this  purpose, 
** chills,"  as  they  are  called,  may  be  solid  or,  if  the 
mold  is  large,  hollow  to  permit  the  passage  of  steam 
for  drying  and  of  water  for  the  rapid  cooling  of  the 
pour. 

The  process  permits  castings,  known  as  chilled-iron 
castings,  to  be  made,  of  which  some  parts  will  have 
the  composition  and  machining  qualities  of  ordinary 
grey  iron,  while  the  parts  that  have  come  in  contact 
with  the  ** chill"  may  be  almost  glass  hard.  The 
metal  used  for  the  process  is  usually  high  grade,  hav- 
ing small  contraction,  and  being  melted  in  air  fur- 
naces.    Car  wheels  and  iron  rolls  furnish  examples 


THE  FOUNDRY  43 

of  such  work,  and  some  foundries  make  this  their 
specialty. 

Malleable   Iron.-Malleable   or   white   iron   has   a 
strength  between  that  of  grey  iron  and  cast  steel,  or 
about    30,000    to    35,000    pounds    ultimate    tensile 
strength   to   the   square   inch.     While   it   cannot   be 
forged  It  can  be  bent  and  twisted,  and  resists  shocks 
well.    It  IS  cheaper  than  cast  steel  and  better  adapted 
tor  small  work.     When  cast  it  is  known  as  ^*  white 
iron     and  is  hard,  crystalline,  and  very  brittle     The 
cast  metal  is  annealed  by  heating  in  scale  or  iron 
oxide  at  a  temperature  of  about  1350  degrees  Fahren- 
heit for  several  days  and  then  cooled  very  slowly 
This  process  burns  out  some  of  the  carbon  and  con^ 

r.       tl  '''*  I''"'  *^"  '^^^^^^^  *^  the  graphitic 

a     'n.  ^^r^'^'i''  ^^'^  ^''^  ^^^  i«  then  known 
as     malleable  iron." 

Cast  Steel-Cast  steel  is  classified  by  the  way  it  is 
melted  as  electric  furnace,  crucible,  acid  open  hearth 
basic  open-hearth,  and  bessemer.  The  electric  fi/ 
nace  and  crucible  methods  are  used  onrfo  %ty 

iSelttl  T'*"''!  '"^  ''"^"  ^«^«"^«-    Open-hearth 
steel  IS  the  cheapest  and  most  used.    It  is  strono-  and 

0  000  pounds  per  square  inch.    It  requires  a  high 
lieat  for  melting,  about  3300  degrees  F    is  mnS 

e  mold  poorly  has  a  shrinkage  nearly  double  that 

t  nls  T  r  .'''"""  '"  ^""^^'^'l  t°  r^'ie-e  the 
m  ed  to  /„v  ""''^r  .'"■"'"^-  ^'^^y  risers  are  re- 
Ztl  VT  ""^  ^^'  shrinkage.  Because  of  these 
"nd  the  rough  character  of  the  product,  steel  found! 


u 


THE  MECHANICAL  EQUIPMENT 


ries  are  still  confined  to  work  of  medium  and  large 
sizes.  Cast  steel  is  supplanting  large  forgings  be- 
cause it  is  cheaper,  and,  in  general,  more  reliable, 
especially  where  the  forgings  are  built  up  by  welding, 
such  as  locomotive  and  ship  frames.  The  art  of  cast- 
ing steel  is  developing  rapidly  and  it  is  gradually 
being  utilized  for  smaller  and  smaller  work. 

Alloys.— The  principal  metals  used  in  the  various 
alloys  are: 

a.  Copper:    A  tough,  malleable,  ductile,  non-corrosive  metal 

which  is  a  good  conductor  of  electricity  and  casts 
poorly.  It  is  quoted  commercially  as  lake,  electrolitic, 
and  casting  copper. 

b.  Tin:    A  crystalline  metal,  malleable  at  ordinary  tempera- 

tures. 

c.  Zinc :    A  hard  and  weak  metal,  which  oxidizes  slowly.    In 

the  form  of  sheets  it  is  known  as  zinc;  in  ingots  as 
spelter. 

d.  Lead:     A   very  malleable,   soft,   and   weak   metal;   little 

used  except  in  bearing  metals,  where  it  is  important. 

e.  Phosphorus:    An  element  never  used  in  the  pure  state; 

ordinarily  it  is  used  in  the  form  of  phosphor-tin  which 
carries  about  5  per  cent  phosphorus.  Phosphor-bronze 
mixtures  contain  from  90  to  96  per  cent  of  copper,  10 
to  about  3%  per  cent  tin,  and  about  14  per  cent  of  phos- 
phorus. They  are  tough,  very  strong,  and  resist  cor- 
rosion. 

f.  Aluminum:     (See  below.) 

There  are  a  great  number  of  foundry  alloys  differ- 
ing widely  in  composition  and  physical  properties. 
The  two  principal  alloys  are  brass,  which  is  com- 
posed of  copper,  zinc,  and  tin;  and  bronze,  which  is 
composed  mainly  of  copper  and  tin.  Even  these  two 
are  subject  to  wide  variation  according  to  the  pur- 
pose for  which  they  are  intended. 


THE  FOUNDRY  45 

Brass  foundries  naturally  deal  with  smaller  cast 
mgs  than  iron  foundries,  for  the  material  hank^^^^^^ 
much  more  valuable;  but  the  number  of  casdngs    s 

ine  brass  used  m  small  castings  is  tough,  non-cor 
rosive,  and  a  good  ^^body-  for  plating.    Owing  to  the 

small  quantities  in  crucibles,  or  by  oil  or  gas  fur- 

Ahiminum  foundries  are  of  increasing  importance 
particularly  in  the  manufacture  of  automoXpar  s 
t'T'"''  ?f"  characteristics  follow  those  of  brass 

S;?  if  ™"- j«  -^t,  very  ductile,  and  no" 
corrosive.    It  is  a  good  conductor  of  electricitv   h«. 

h«+  ^  .  rf^^^'^'^tic  quality  is  its  extreme  lightness  • 

t.e^l^^'^Sest.ft'^^^^^^^ 

flasks    Zm    It    ''''"''    '""^    transportation    !t 
-gh\XireLS„r  •""""  ""''-'  '^'  '' 

walls  be?rfil7ed  in  w^f'  ""^  '''^'  ^^^''  '^^  «"ter 
buildinTshouM  b.  T    "Tr'^r  ^"•"^-    The  main 

-reThttr  '"?  -"  --  trwi^dLThtn^t 

CoviL  o%?v:tt-Tr\^f  "'"^°^  --  '^«"d 

aea  to  give  sufficient  light.    The  lighting,  so  far 


/  '4 


If 


i  I 


46 


THE  ME(  HANICAL  EQUIPMENT 


as  possible,  should  come  from  the  side  walls,  as  side 
windows  are  easier  to  clean  and  will  stay  clean  longer. 
The  best  method  of  heating  and  ventilating  is  the  in- 
direct fan  system,  where  fresh  air  is  drawn  in  from  the 
outside,  heated,  if  necessary,  and  delivered  to  all  por- 
tions of  the  building.  Ample  provision  should  be  made 
for  the  escape  of  gases  and  smoke  through  the  clear 
story  at  the  top  of  the  roof .  The  floor  should  consist  of 
molding  sand,  the  depth  varying  with  the  class  of 
work  to  be  done*  A  foundation  of  clay,  well  rolled 
down,  will  help  greatly  in  keeping  the  molding  floor 
in  good  condition  and  prevents  the  moisture  from 
draining  into  the  ground.  Figures  5  and  6  give  a 
plan  and  cress  section  of  a  foundry  for  general  work. 
The  arrangement  will  vary  widely  with  different 
eases,  but  the  one  shown  will  illustrate  the  relation 
of  the  various  processes. 

The  office.  A,  should  be  centrally  located,  with  a 
good  view  of  the  main  floor  and  partitioned  off  from 
it  by  glass  to  render  it  as  free  as  possible  from  dust. 
It  should  be  on  the  side  nearest  the  pattern  shop.  A 
temporary  storage  equipped  with  low  tables  and 
shelves  for  patterns,  B,  is  provided  outside  of  the  of- 
fice. Here  the  foreman  and  his  assistants  can  check 
the  patterns  as  they  come  in  and  hold  them  for  issu- 
ance to  the  molders.  The  heavier  work  will  be 
molded  on  the  floor  of  the  main  bay  where  it  can  be 
served  by  the  overhead  cranes,  which  are  necessary 
for  handling  the  large  flasks,  cores,  and  pouring 
ladles,  and  for  lifting  the  castings  from  the  mold. 
The  large  green-sand  castings  may  be  made  at  one 
end,  C,  nearest  to  the  flask  storage,  D,  which  is  in 


THE  FOUNDRY 


47 


6fondarJ  Ciiuqe\R.R.   j 


_    ^t  ^'^'^  ^^'"'''9^'  or?  Cfyorgmg  F/oor  ^  leye/ 


TOS.  5  AND  6.      PLAN  AND  SECTION 


OF  A  GRAY  IRON  FOUNDRY 


/ 


I]  4 

\}  'I 


I]    . 


^1^ 


48 


THE  MECHANICAL  EQUIPMENT 


the  yard  outside.  Flasks  for  the  dry-sand  and  loam 
molds  may  be  brought  in  from  the  opposite  end,  but 
as  the  loam  work  is  the  heaviest  it  should  be  so  lo- 
cated as  to  involve  the  least  transportation.  The 
loam  and  dry-sand  core  work  should  be  located  con- 
veniently with  respect  to  the  ovens,  F,  used  for  dry- 
ing the  cores  and  molds.  The  core  shop  may  be  in  a 
separate  building  or,  if  under  the  same  roof,  should 
also  be  near  the  ovens. 

Light  floor  work  and  machine  molding  may  be  lo- 
cated in  the  side  bays  where  the  light  is  good  and  the 
transportation  problem  is  less  important.  The  mold- 
ing machines  may  be  placed  to  advantage  on  the  side 
nearest  the  sand  storage  to  permit  the  use  of  over- 
head belt  or  bucket  conveyors  and  chutes  for  deliv- 
ering the  sand  directly  to  the  flasks  on  the  machines. 
The  sand  mixing  should  be  located  between  the  sand 
bins  and  the  main  floor.  Air-operated  sifters  and 
mixers  facilitate  this  work.  The  cupolas  should  be 
centrally  located,  with  the  bull  ladles  under  the  main 
crane.  In  large  foundries  there  will  be  two  or  more 
cupolas,  in  order  that  different  mixtures  may  be 
melted  simultaneously.  Small  cupolas  are  often  in- 
stalled near  the  floor  for  light  work  to  serve  that 
floor  alone.  Blowers  should  be  placed  near  the  cu- 
polas to  avoid  long  wind  pipes. 

The  cleaning  department  should  be  located  either 
at  the  end  of  the  foundry  or  outside.  Sufficient  space 
should  be  provided  to  pile  the  castings  as  they  are 
brought  from  the  floor  and  to  give  sufficient  room  for 
men  to  work.  Small  castings  will  be  cleaned  in  tum- 
bling barrels,  or  in  pickling  tubs,  or  by  the  use  of 


THE  FOUNDRY 


49 


emery  wheels.  As  this  work  is  of  necessity  very 
dirty  and  involves  fumes,  it  is  well  to  have  it  in  a 
separate  building  or  room.  Very  large  castings  are 
usually  cleaned  on  the  main  floor,  and  air  chipping 
hammers  are  indispensable  in  this  work.  In  fact, 
compressed  air  has  become  the  handy  man  of  the 
foundry;  it  is  distributed  about  the  foundry  in  pipes 
and  flexible  hose  at  about  80  pounds  pressure,  and  is 
used  for  operating  the  molding  machines,  for  blowing 
out  the  molds  and  for  lifting  the  small  flask  molds 
and  cores. 

Storage.— The  pig  iron  is  stored  outside— in  the 
illustration  it  is  on  an  upper  level,  even  with  the 
charging  room  floor.  The  topography  here  allows  the 
use  of  a  standard-gauge  railroad  spur  outside  and  up 
to  this  level,  which  permits  the  unloading  of  the  pig 
iron  and  coke  on  that  level  and  the  delivery  of  the 
sand  by  gravity  into  the  bins,  M,  underneath  the 
track  on  the  level  of  the  main  floor  where  it  will  be 
used. 

Transportation—The  main  bay  is  provided  with 
travelmg  cranes  which  are  heavy  enough  to  handle 
t he  largest  flasks,  ladles,  and  castings.  Lighter  trav- 
elmg  cranes  may  be  installed  under  the  bays  for  simi- 
lar service  on  medium-sized  work,  and  it  is  desirable 
to  have  jib  cranes  in  addition.  The  traveling  cranes 
should  be  used  for  general  transportation  from  one 
part  of  the  building  to  another;  the  jib  cranes  for 
local  work.  The  setting  of  heavy  cores  and  molds 
trequently  takes  considerable  time,  and  the  overhead 
crane  is  too  valuable  a  machine  to  be  tied  up  with  this 
work  when  other  parts  of  the  foundry  may  be  need- 


/ 


\ 


It 


I     t! 


|M    I 


50 


THE  MECHANICAL  EQUIPMENT 


ing  its  service.  The  best  practice,  therefore,  provides 
a  combination  of  jib  and  traveling  crane  service  for 
this  heavy  work;  while  for  light  work,  overhead 
tracks  and  trolleys  combined  with  air  hoists  are  very 
efficient.  The  overhead  trolley  leaves  the  floor  free 
from  obstructions  and  clear  for  setting  out  the  molds. 
Standard-gauge  railway  tracks  should  enter  the  main 
foundry  floor  in  order  that  the  overhead  cranes  may 
load  the  larger  castings  from  the  floor  directly  upon 
railway  cars  for  shipment  to  other  departments  or  to 
outside  plants.  Wherever  possible,  the  molten  iron 
should  be  distributed  by  cranes  or  overhead  trolleys; 
the  use  of  industrial  railways  for  this  purpose  is  in- 
efficient and  dangerous.  Industrial  railway  tracks 
will  provide  for  bringing  in  the  flasks,  patterns,  and 
sand  and  for  transporting  patterns  and  cores.  Turn- 
tables are  preferable  to  curves  on  industrial  railways 
inside  of  a  building,  for  they  are  more  economical  of 
space  and  the  nuisance  caused  by  cars  jumping  the 
tracks  on  sharp  curves  is  avoided.  However,  the  sub- 
ject of  transportation  is  handled  elsewhere  in  this 
series,  and  the  reader  is  advised  to  consult  that  vol- 
ume for  full  information.* 

Clean,  sanitary  lockers  and  washrooms  are  a  part 
of  modern  foundry  equipment.  Foundry  work  at  best 
is  dirty;  but  foundry  workmen  are  as  self-respecting 
as  any  others,  and  haphazard  washing  facilities  and 
dirty  clothes  hanging  along  the  walls  are  neither  san- 
itary nor  conducive  of  self  respect. 

In  the  arrangement  shown  in  Figure  5,  the  patterns 

♦See  "Handling  Material   in  Factories,"  by  William  F.  Hunt, 
Factory  Management  Course. 


THE  FOUNDEY 


51 


come  in  from  one  side  of  the  foundry,  the  supplies 
from  the  other,  and  the  flasks  from  one  end,  E.  The 
general  movement  of  material  is  from  right  to  left 
and  out  on  the  railway  tracks  at  the  left  end.  The 
foundry  shown  is  for  general  work  suitable  for  han- 
dling light  and  heavy  grey-iron  castings.  In  brass 
foundries  where  the  work  is  light  and  in  steel  foun- 
dries where  it  is  heavy,  there  would  naturally  be  a 
somewhat  different  arrangement,  although  many  of 
the  features  would  be  similar. 


\ 


CHAPTER  V 
FOUNDRY  MOLDING  METHODS 

Materials. — Foundry  molding  is  divided  into  four 
well  recognized  branches — green  sand  work,  dry  sand 
work,  loam  work,  and  core  work.  The  first  three  give 
their  names  to  corresponding  types  of  foundries,  ac- 
cording to  the  type  of  molding  which  prevails.  Core 
work  is  common  to  all  three. 

In  green  sand  foundries  the  molds  may  be  poured 
as  soon  as  they  are  made,  and  because  of  the  quick- 
ness and  cheapness  of  the  process  this  is  the  common- 
est method  of  making  castings. 

In  dry  sand  molding  a  core  sand  mixture  is  used 
next  to  the  pattern  and  the  mold  is  baked  after  the 
removal  of  the  pattern.  The  baking  drives  off  all 
moisture  and  leaves  a  hard,  clean  surface.  It  is  used 
where  the  rush  or  bulk  of  metal  would  spoil  a  green 
sand  mold. 

Loam  work  consists  of  building  up  a  mold  of  brick 
on  which  a  facing  of  mortar  is  placed.  The  correct 
form  is  sometimes  given  to  the  mold  by  a  full  pattern, 
more  often  by  a  skeleton  pattern  or  a  sweep,  after 
which  the  entire  mold  is  baked.  Loam  work  is  used 
for  heavy  castings  where  the  pieces  are  few,  and  calls 
for  more  skill  than  any  other  form  of  molding. 

The  principal  supplies  used  in  molding  are  sands, 

52 


FOUNDRY  MOLDING  METHODS  53 

loam,    facings,   fire   clay,   parting   dust,    and    core 
binders. 

Moldingr  Sands.— Good  molding  sand  may  be  light, 
medium  or  heavy.    It  must  be  porous  enough  to  al- 
low  the_  escape  of  air,  steam,  and  the  gases  generated 
in  pouring,  and  at  the  same  time  compact  enough  to 
hold  Its  shape  and  withstand  the  rush  of  metal     It 
must  be  refractory  to  withstand  the  high  tempera- 
tures   and  It  must  not  have  any  chemical  reaction 
with  the  molten  metal.    It  must  be  readily  removed 
from  the  casting  and  leave  a  clean,  smooth  surface. 
The  selection  of  proper  sand  is  of  vital  importance: 
It  IS  largely  a  matter  of  experience  and  one  of  the 
essential  elements  in  a  foundryman's  skill 
wS  f  °'*  ™P«^tant  element  in  the  sand  is  siUca, 
which  forms  about  85  per  cent  and  gives  the  requi- 

r  1  Al  rf '.?  *^"^?^-  ^^  ^^'  percentage  of  silica 
luns  too  high,  the  sand  will  crack  in  drying  and  the 
mold  w,l  not  pack  and  will  not  be  impervious  to  the 
metal.  Alumina,  or  clay,  the  other  important  element 
comprises  about  8  or  9  per  cent  of  the  composition- 
1  furnishes  the  bonding  quality  and  renders  the  sand 
pks^c  and  cohesive.    Magnesia  also  acts  as  a  bo^d 

be  lost.    The  lime  and  metallic  oxides  that  are  nres- 

h  uM  Tf  ""';  r  ^^™^"^-    Th«  -etalliT  ox' des 
should  not  exceed  4  per  cent  nor  the  lime  1  per  cent 
Sand  used  in  brass  foundries  runs  about  10  per  cent 

ower  in  silica  and  is  higher  in  iron  oxide.    For  smTu 
cas  ings,  as  there  is  less  need  of  venting  I   ZT 

flTLlo   ''  ""'''  ^f'''  -*-"-e%rumta' 
tiian  the   coarser-gramed   sand   required   for  heavy 


if 

Ni 


54 


THE  MECHANICAL  EQUIPMENT 


castings;  since  the  heat  is  less  the  sand  need  not  be  so 
refractory  and  may  contain  less  silica. 

Free  sands  contain  about  98  per  cent  of  silica  and 
have  less  than  2  per  cent  of  alumina.  There  are  two 
kinds,  river  and  beach  sand.  River  sand  is  made  up 
of  sharp,  chipped  grains  and  makes  a  very  strong 
core.  Beach  sand  is  smooth  grained  and  used  only 
for  small  cores  and  for  parting  sand. 

Loam. — Loam  is  a  soil  composed  chiefly  of  silica 
sand,  clay,  and  carbonate  of  lime,  with  some  oxide 
of  iron  and  magnesia,  and  decayed  animal  and  vege- 
table matter.  Next  to  molding  sand  it  is  the  most  im- 
portant material  used  in  the  foundry.  It  parts  with 
its  water  at  red  heat,  and  at  the  temperature  of 
molten  iron  the  carbonate  of  lime  will  fuse  and  be- 
come vitrified.  Black  loam  is  a  cheap  variety,  hav- 
ing strong  binding  properties  and  is  used  for  setting 
the  brick  work  in  loam  molds. 

Facing. — Facing  is  usually  some  form  of  carbon 
such  as  graphite,  charcoal  or  coke.  It  is  used  to  give 
a  smooth  surface  to  the  face  of  the  mold  and,  as  it 
burns  slowly  under  the  heat  of  the  metal,  it  forms  a 
thin  film  of  gas  between  the  iron  and  the  sand,  pre- 
venting the  sand  from  burning  into  the  casting  and 
causing  it  to  separte  from  the  casting  when  cold. 
Facing  should  be  very  finely  ground;  it  must  not  burn 
too  easily,  and  must  adhere  firmly  to  the  face  of  the 
mold  so  that  it  will  not  be  washed  away  by  the 
molten  iron.  Blacking,  as  it  is  called,  is  a  mixture 
of  facing  with  a  clay  wash  or  molasses  water  which 
is  applied  to  the  finished  surface  of  a  mold  or  core. 
Facing  sand  is  a  combination  of  molding  sand  and 


FOUNDRY  MOLDING  METHODS 


55 


coal  dust,  used  next  the  pattern  on  large  work.  Part- 
ing sand,  which  may  be  burnt  sand,  charcoal,  or 
manufactured  preparations,  is  used  between  the  flask 
and  the  cope.  It  must  be  absolutely  non-tenacious,  so 
that  there  will  be  no  adherence  between  the  two 
pieces. 

Cores  and  Core  Binders.— Cores  are  sand  shapes 
which  partially  fill  the  impression  in  the  mold  and 
thereby  form  the  holes  or  hollows  in  the  castings. 
They  are  generally  supported  by  extensions,  known 
as  core  prints,  which  extend  into  the  body  of  the 
mold.    The  conditions  required  of  cores  are  exacting. 
They  must  be  strong  to  resist  flotation  and  being 
washed  away;  they  must  be  highly  refractory  be- 
cause they  are  almost  completely  surrounded  with 
molten  metal,  and  yet  after  the  casting  has  cooled,  it 
must  be  possible  to  remove  them  completely  and  eas- 
ily.   To  accomplish  these  purposes  they  are  made  of 
free  sand  containing  little  or  no  alumina  which  would 
cause  them  to  cake  and  make  them  hard  to  remove. 
The  core  sand  is  mixed  with   binder,   a  vegetable 
compound  of  ordinary  wheat  flour  with  rosin,  linseed 
oil  and  molasses.     When  the  cores  are  formed  they 
have  little  or  no  strength  and  are  too  weak  for  use 
m  the  mold.     To  give  the  necessary  strength  they 
are  heated  in  ovens  to  bake  the  binder  and  give  it 
the  strength  required.     When  the  mold  is  poured, 
the  high  temperature  of  the  molten  metal  burns  out 
the  binder  and  reduces  the  core  to  a  mass  of  loose 
sand  which  can  be  dug  out  with  ease.    As  it  takes 
time  for  the  binder  to  burn  and  the  gases  to  escape, 
the  core  retains  its  strength  long  enough  for  the  metal 


.1 


i  .. 


56 


THE  MECHANICAL  EQUIPMENT 


to  set.  Cores  are  frequently  strengthened  with  iron 
rods,  pipe,  and,  at  times,  with  specially  east  core 
irons.  Where  these  are  not  sufficient,  chaplets,  which 
are  small  supports  made  in  many  varieties  and  shapes 
are  used.  It  is  intended  that  they  fuse  into  the  cast- 
ing, but  they  are  at  best  a  necessary  evil  as  they 
weaken  the  casting  in  three  ways — ^by  the  introduc- 
tion of  a  foreign  metal,  by  the  formation  of  porous 
spots  about  the  chaplet,  and  sometimes  by  a  failure 
to  fuse.  They  are  necessary,  however,  in  many 
classes  of  work. 

Cope  and  Drag. — Molds  are  made  in  flasks  consist- 
ing of  two  or  more  rectangular  frames  of  the  same 
length  and  breadth,  the  upper  one  known  as  the  cope 
and  the  lower  one  as  the  drag  or  nowel.  When  there 
are  three  parts,  the  middle  one  is  known  as  the  cheek. 
The  frames  are  used  to  hold  the  sand  while  the  im- 
pression of  the  pattern  is  being  made.  They  are 
made  of  wood,  cast  iron,  or  pressed  steel.  Iron  and 
steel  flasks  should  be  used  for  standard  work ;  wooden 
flasks  are  much  cheaper,  but  they  deteriorate  rapidly 
and  must  be  handled  with  care.  The  copes  of  large 
flasks  usually  have  crossbars  to  help  in  holding  the 
sand  in  place.  The  cope  and  drag  are  made  to  reg- 
ister with  each  other  by  means  of  guide  pins  and 
sockets.  In  the  ordinary  type  of  flask  the  mold  re- 
mains in  the  flask  while  the  casting  is  being  poured, 
necessitating  the  use  of  as  many  flasks  as  there  are 
molds. 

''Snap  flasks"  resemble  ordinary  flasks  except  for 
the  fact  that  they  are  hinged  at  one  corner  and  are 
provided  on  the  diagonal  corner  with  latches,  so  that 


FOUNDRY  MOLDING  METHODS  57 

StedTiLt'  T?^  'r^^  ^'^''  ^^'  ^^^^  i«  f«™^d  and 
hfted  clear  of  it.     They  are  used  for  small  work 

where  the  mold  is  strong  enough  to  stand  the  pres 

a  mold  IS  in  place  on  the  floor,  the  flask  is  taken  off 

snaV  flask  i"  "'"''5  ?^  "^^^  ^^^-    ^--'  ^^t  one 

T''ro^^L''H"'''T  "^^'^"^   '^'^'  ^--tities. 

mold      A  ^^  ^^.T,1  ?^''''"  ^''  P^^^^^  i^  "taking  the 
I  ter  of  pT  '\'  ''™  "^^^^  ''  '^-^^  -1^  or 

mai^^J^thP  ^  ^'""V^.  ''  "^^^  ^«  a  «^old  board  for 
making  the  cope.  Sand  matches  are  used  only  where 
a  few  castings  are  needed,  while  the  plaster  of  Paris 
matches  may  be  used  indefinitelv.  Matches  are  made 
m  shallow  frames  the  size  of  thJ  flask  tole  used  and 

arp  «mon  6  ^»A  excess  sand    and  slicks,  which 

withdrawn  In  LT  ^^""^  ^^^  P^"«™  has  been 
Dl  1  rV  '^'''*'*'"  *"  th^^e  there  will  be  snrue 
plugs  which  are  cylindrical  nia<,«.o     t         -,        ^ 

"•aking    the    runneV  th^ugh"^  wh  eh    T     "f?  '" 

poured;  draw  sDikes  and  hT  ,1  **"  ™^*^'  ^« 
injr  ihl      7/  ^  '^^^^  plates  to  help  in  lift 

'ug  the  pattern,  and  vent  rnHo  f,^^       i  •     ^ 

for  the  escape  ^f  gases  ''''"^  ^^''^^'' 


It,'.   '■• 


)■ 


jvii'^ 


/ 


58 


THE  MECHANICAL  EQUIPMENT 


ii 


Making  a  Mold. — The  first  operation  of  importance 
in  making  a  mold  is  the  preparation  of  the  sand — that 
is,  mixing  the  proper  proportions  of  old  and  new  sand 
and  tempering  the  mixture.  Too  much  new  sand 
causes  the  mold  to  crack,  as  it  will  not  vent  properly; 
not  enough  causes  the  cutting  or  washing  away  of 
the  mold. 

Tempering  is  done  by  moistening  the  sand  with 
water  until  a  handful  of  it  can  be  squeezed  into  a 
firm,  egg-shaped  lump  that  will  break  cleanly  with- 
out crumbling.  Too  little  tempering  gives  a  weak 
mold;  too  much  tempering  produces  an  excess  of 
gases. 

The  next  operation  is  the  ramming  of  the  drag 
and  then  the  cope,  that  is,  sand  is  shoveled  into  the 
flask  and  is  packed  around  the  pattern.  If  the  sand 
is  rammed  too  hard,  blow-holes  may  result  because 
the  natural  vents  or  air  cavities  are  filled  up;  and  if 
it  is  not  rammed  hard  enough  it  will  sink  under 
the  weight  of  the  metal  or  be  washed  away.  The 
joint  of  the  mold  where  the  two  parts  come  together 
should  be  rammed  hard,  as  it  is  exposed  to  handling. 
In  general,  the  mold  should  be  as  soft  as  possible  and 
still  retain  its  shape.  Gaggers,  which  are  L-shaped 
pieces  of  iron,  may  be  set  in  the  mold,  when  neces- 
sary, to  give  it  the  requisite  strength. 

When  the  mold  is  formed,  it  is  vented.  This  is  ac- 
complished by  opening  up  passages  for  the  escape  of 
gas,  air  and  steam.  If  this  is  not  done,  the  mold  may 
explode,  or  some  parts  may  not  be  filled  with  iron  on 
account  of  the  pocketing  of  gas  which  cannot  get 
away.    New  sand  needs  a  good  deal  of  venting.    Af- 


FOUNDEY  MOLDING  METHODS  59 

ter  venting  the  mold,  an  opening  is  formed  through 

Lslh  J:  "''f  'V  '""''^  ^^^  ^''^'    This  opening 
has  three  parts,  known  as  the  pouring  basin,   the 

runner  or  sprue,  and  the  gate.     Making  it  proper^ 

sible  for  many  bad  castings.  The  gates  should  be 
large  enough  to  fill  the  whole  mofd  quickly,  and 
should  be  located  so  that  the  metal  will  rise  into  the 

Tound'off^R'^'  ''^  '''''''  ^^'  ^^  machined  0 

frZthf^rr.  '?  ""''^''^^  "P^"^^^«  ^^tending 

s  r^e  XZT^T"  '"  '^'  *^P  '^  '^'  --Id;  they 

Sland  r  TT'''  ^'  "  "^'^^^  ^«  ^  skimming 

.ate,  and  as  a  supply  for  additional  metal  to  make  ud 
the  shrinkage  in  cooling  ^ 

nefd^'o'ml'^'jfv '"  ^'  ^"^^^  ^^^  ^''^  -i"  often 
Zl     I    1!  P^*"^^«^'  ^«d  ^  good  molder  will  repair 

done  with  the  fingers  wherever  possible.     The  mold 

is  aTd :::''  ^r  rr'  ^^^^^^  ^^^^^-^  ---^e 

^as  and  causes  blow  holes;  too  little  facing  results  in 

nalt  and  the  mold  is  ready  for  pouring 

exS  S  ""''^^"^  i'  .'™^^"'  *^  ^^^^^  «-^d  work 
except  that  core  sand  is  used  next  to  the  pattern 

rml'r;''t  l^^^  ^^^^^^^  --d-     After  the  S 
IS  made  It  is  baked  or  dried  and  is  then  given  a  coat 

to  !  '    ^fi:  .^'^  '"^^  "^^^^^  ^'^  -^-de  in  iron  flasks 
0  permit  their  being  placed  in  the  oven.    It  is  neces 
ary    0  vent  dry  sand  molds  also,  not  because  therp 
s  moisture  in  them,  but  the  gase    from  the  burnrn^ 

facing  must  be  parnpH  «fF  *«  •  ourning 

s  «iu&i  oe  cdiiied  oif  to  xnsure  a  sound  casting 


[*'i 


^'-i.. 


/ 


60 


THE  MECHANICAL  EQUIPMENT 


Machine  Molding.— Molding  machines  are  used 
with  great  advantage  in  green  sand  foundries  wher- 
ever there  is  repetition  work.  Not  only  do  they  in- 
crease production,  but  they  materially  improve  the 
quality  of  the  castings,  which,  in  turn,  decreases  the 
cost  of  the  machining  operations.  They  have  the  fur- 
ther advantage  that  they  may  be  operated  by  com- 
paratively unskilled  labor.  They  may  be  classified 
under  four  general  types,  stripping-plate  machines, 
squeezers,  roll-over  machines,  and  jarring  or  jolt  ram- 
ming machines. 

The  stripping-plate  type  of  machine  is  used  for 
work  which  offers  difficulties  in  drawing  the  pattern 
from  the  sand.  The  stripping  plate  itself  is  sup- 
ported rigidly  on  the  machine,  the  patterns  being 
mounted  on  a  drop  plate  working  in  guides.  The 
stripping  plate  is  cast  to  leave  openings  about  one 
inch  wide  around  the  pattern.  When  the  stripping 
plates  and  the  patterns  are  properly  set,  this  space 
is  filled  in  with  Babbitt  metal,  so  as  to  form  a  close 
fit  around  the  patterns  at  the  parting  line.  In  opera- 
tion, the  flask  is  placed  on  the  machine,  is  rammed, 
vented,  and  struck  off  on  the  top;  the  pattern  is  then 
withdrawn  downward  through  the  stripping  plate  by 
a  hand  lever  or  an  air-operated  cylinder,  and  the 
mold  is  removed  and  set  out  on  the  floor.  As  pointed 
out  in  Chapter  III,  the  impressions  in  gated  patterns 
may  be  so  arranged  as  to  make  one  plate  serve  for 
both  the  cope  and  drag  parts  of  the  mold.  Stripping- 
plate  machines  are  well  adapted  to  the  manufacture 
of  gears,  pulleys,  etc.,  having  straight  or  nearly 
straight  sides. 


FOUNDRY  MOLDING  METHODS  61 

The  squeezer  type  of  machine  may  be  operated  by 
hand  and  merely  packs  the  sand.    In  it  the  patterns 
may  be  carried  on  the  two  sides  of  a  plate  which  is 
set  between  the  cope  and  drag.    Both  boxes  are  filled 
with  sifted  sand  and  set  on  the  machine.    A  lever  or 
air  cylinder  is  used  to  compress  the  sand  against 
the  plates.    The  cope  is  then  lifted  from  the  plate, 
the  plate  is  lifted  from  the  drag,  and  the  two  parts 
of  the  mold  are  set  on  the  floor  ready  for  pouring. 
Ihis  type  of  machine  is  used  chiefly  for  thin  work 
which  vents  easily  and  cools  quickly,  for  the  outer 
surfaces  of  the  mold  are  apt  to  be  rammed  so  hard 
that  they  would  choke  the  venting  of  heavy  castings 
In  another  type  of  squeezer  the  cope  and  drag  flasks 
are  side  by  side,  and  the  patterns,  instead  of  being 
carried  on  two  sides  of  the  plate,  are  arranged  on 
the  same  side,  the  cope  impression  being  over  the 
flS  ^^^^  ^""^  *^^  ^""^^  impression  over  the  drag 

In  the  roll-over  machine  the  pattern  is  carried  on 
the  top  of  a  match  plate;  a  flask  is  placed  over  it  and 
the  mold  IS  rammed  by  hand  or  squeezed.  The  mold 
and  pattern  are  then  rolled  over  and  the  pattern  is 

time.  The  match  plate  with  the  pattern  is  then  rolled 
back  into  its  original  position  ready  for  making  the 
next  mold.  (See  Figure  7.)  All  three  of  the  above 
ypes  may  be  operated  by  hand  or  by  power,  and 
snap  flasks  are  generally  used.  The  production  of  a 
power  squeezer  will  exceed  that  of  a  hand  squeezer 

will  handle  a  mold  weighing  1000  pounds  or  more 


% 


:/■ 


'I 

I 


j 


PIG.     7.      HAND-OPERATED    ROCK     OVER     MOLDING     MACHINE 

Henry  E.  Pridmore. 


il 


FIG.    8.      MOLDING    MACHINE    AND    SECTIONAL    VIEW 

American  Molding  Machine  Co. 

62 


FOUNDRY  MOLDING  METHODS  63 

foTl'Jl'''  jolt-ramming  machine,  Figure  8,  is  used 
for  al  classes  of  work  up  to  the  largest  floor  work 
made  in  green  sand;  the  only  limit  is  the  capacity 
of  the  machine  itself,  which  varies  from  a  few  hun- 

moltiH  "T  ^''""'^"^  P°""^«-  The  patterns  are 
mounted  on  heavy  pattern  or  match  plates;  the  flask 
IS  put  in  place,  filled  with  sand,  and  clammed  to  the 
pattern  plate.  It  is  then  lifted  and  placed  on  the 
jarring  table  which,  in  large  machines,  is  on  the  , eve 
of  the  tmmdry  floor,  the  working  parts  being  below 
on  a  rigid  concrete  foundation.    The  table  is  "joS- 

2ut  thoM  ^^"^  L""  ^"  ^°^"'  ^^'^^S  the  sand 
about  the  pattern.  The  number  of  blows  required  is 
de  ermined  by  experience,  but  the  time  needed  s 
onb-  --11  fraction  of  that  consumed  by  hand  ram! 

are  made,  and  many  of  their  operations  are  automatic 
Some  are  better  adapted  to  certain  classes  of  To  k 

han  others  and  intelligent  selection  of  the  type  best 
suited  to  the  work  in  hand  should  be  made. 

earner  Poundries.-The  full  capacities  of  machine 
mo Iding  are  best  realized  in  carrier  foundriesTa  sne 

r sot   n  °'  'T  ''''  '^-^'^y^  where  thi'm^^; 
passes  bvt^e      "I"'  '•'  ^''"'^  "P*^"  ^  ''^"•^er  which 

Hoor     In  tt      7      "'  T^'^^  °*  "^'"^  '^^  «»t^  on  the 
noor.    In  the  ordinary  type  of  foundry  the  mold«  «r« 

^Z^  ""^  ''"•^^f  '^^''  -^  towVrd  the  e'nV 
e  day  the  pounng  is  done  by  the  molders  who  brine 
l>e  molten  iron  to  the  molds.    In  the  carrier  founZ 
the  pouring  is  done  continuously  througho.     ZZl 


.:.!)! 


I 


FKi.     7.       Il\SI>-<>l'i:iiATKn     ROCK     OVKK      MOT.DlNci      MA<'mNE 

llflliv  K.   I'liillllolc'. 


FIG.     8. 


>101.[)IN(i     MACHINE    AND    SECTIONAL    VIEW 
AiiuTiitin    Miildinj:   Macirnic  ('". 
•52 


FOUNDRY  MOLniNO  METHODS 


63 

foJ''.ir'"i''  "*'■  J"'V""'"""«  '""^''''"^  f''ig"'-e  8,  is  used 
fo.   all  classes  of  work  up  to  ti.e  largest  floor  work 

nade  ,n  green  sand;  the  only  limit  is  tl.e  capacity 
of  the  machine  itself,  which  varies  from  a  few  hun- 
.Ired  to  many  thousand  pounds.  The  patterns  are 
."«.„,  ed  on  heavy  pattern  or  match  plates;  the  flask 
-  put  ,n  place,  filled  with  sand,  and  damped  to  the 

"•'«>.'■'"/";*"•  ,.It  is  then   lifte<I  and   placed  on   tie 

arnng  fal.le  wh  ch,  in  large  machines,  is  on  the  level 
"f  the  loundry  floor,  the  working  parts  being  I.elow 
<"'  a  n«id  concret,.  foundation.    The  table  is  "jolteii" 

nd'drr^  ;7';'"'<".-  «•''-•''  W-ts  it  about  four''inches 

.  ''out  the  pattern.  The  number  of  blows  required  is 
.1-'  ertnined  by  experience,  but  the  time  needed  is 
-ly^a  small  fraction  of  that  consumed  by  hll  .t" 

\arioMs  combinations  of  these  tvpes  of  machines 
-e  nuKle.  and  many  of  their  operations  are  au  o    a  i  ' 
Nome  ar<.  better  adapted   to  certain  classes  of    4 S 
"'!  "  others,  and  intelligent  selection  of  the  tvpe  bes 
M.de<l  ,0  the  work  in  hand  .should  be  made 

'"«>  ding  aie  best  realized  in  carrier  foundries  (a  sne 

;;r ;:;  irr;  ■'  't  ■•■•"",'  '•"""^"•>'>  -»'«-  tuiinX; 

•'■  ><>on  as  It  IS  made,  is  placed  upon  a  carrier  which 
.™    y  the  machine,  instead  of  ling  set  ::t  ^ 
"•     I  '  the  ordinary  type  of  foun.lrv  the  molds  -.re 

.■r,;;^'■'•"^'•^ ''';'''"-••  -"'toward  thee: 

'la>  the  pouring  is  .lone  by  the  mohlers  who  bri,,..- 

'"■  niolten  iron  to  (he  uiohls      In  fl.  »'«i>iing 

tlic  i)(,ii,in<r  ;.    I  -  *''*^  carrier  fonm  rv 

l'o""ng  IS  done  continuously  throughonl  (he  day 


II 


< 


t 


1 

1 


64 


THE  MECHANICAL  EQUIPMENT 


by  men  who  do  nothing  else,  the  carrier  bringing  the 
molds  from  the  machines  to  a  portion  of  the  floor  near 
the  cupola  where  the  pouring  is  done.     After  the 
molds  are  poured,  the  castings  cool  as  the  carrier 
progresses;    and    after    a    few    moments    they    are 
knocked  out  of  the  mold  and  run  across  a  set  of  shak- 
ing bars  which  delivers  the  castings  into  a  cooling 
crib,  while  the  sand  falls  through  the  bars  into  the 
hopper  of  an  elevator  and  is  carried  up  overhead. 
New  sand  is  then  added,  and  is  tempered  and  deliv- 
ered by  conveyors  to  chutes  which  open  directly  over 
the  molding  machines.    The  snap  flasks  used  by  the 
molder  remain  at  the  machines,  and  the  molds  are 
poured  either  without  flasks  or  with  only  light  steel 
bands  around  them  to  prevent  shifting.    This  type  of 
foundry  is  very  efficient  for  long  runs  of  small  stand- 
ard castings,  such  as  pipe  fittings,  which  cool  quickly, 
but  is  not  applicable  for  general  work. 


CHAPTER  VI 
FOUNDRY— MELTING,  POUEING,  CLEANING 

General  Methods.— Three  ways  are  employed  for 
forming  metals  for  industrial  purposes: 

First,  by  melting  the  metal  and  casting  it  in  sand 
or  other  molds.  This  forms  the  basis  of  foundry 
work. 

Second,  by  pressing  the  metal  into  the  desired 
form.  This  may  be  performed  while  the  metal  is 
either  hot  or  cold,  either  by  blows  under  a  hammer 
or  by  steady  pressure.  Forming  the  metal  while  hat 
is  known  as  forging;  forming  it  cold,  as  press-work 
or  stamping. 

Third,  by  cutting  the  metal  with  tools  having  single 
or  multiple  cutting  edges.  Grinding  is  simply  a  form 
of  cutting.  This  method  is  usually  used  as  a  supple- 
ment to  the  others  for  machining  castings  or  forgings 
accurately.  The  first  two  methods  are  most  useful 
for  giving  the  material  its  general  form,  but  the  work 
must  usually  be  finished  by  the  last  method  if  it  is  to 
be  close  to  size. 

The  Cupola.— Foundry  metals  are  melted  in  the 
cupola,  in  the  air  furnace,  in  the  open  hearth  fur- 
nace, in  oil  or  gas  furnaces,  in  crucibles,  and  in  the 
electric  furnace. 

Of  these,  the  cupola  is  the  most  widely  used  and  is 

66 


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66  THE  MECHANICAL  EQUIPMENT 

the  one  generally  employed  for  melting  cast  iron.    It 
has  the  highest  fuel  economy  and  is  the  easiest  to 
manipulate.    The  metal  may  be  melted  continuously 
throughout  the  day  and  be  drawn  off  as   desired. 
Figure  9  shows  a  section  of  a  typical  cupola.    It  con- 
sists essentially  of  a  vertical  iron  shell,  A,  lined  with 
fire  brick,  into  which  is  charged  alternate  layers  of 
pig  iron  and  fuel.    The  shell  and  lining  are  carried 
on  a  plate,  B,  supported  by  four  out-spreading  legs 
at  a  height  sufficient  to  allow  the  two  bottom  doors, 
C,  to  swing  clear  of  the  floor.    The  doors  which  form 
the  bottom  of  the  melting  chamber  are  held  up  in 
place  by  a  prop,  D,  while  the  cupola  is  in  operation, 
and  are  protected  during  the  heat  by  a  bed  of  sand. 
When  the  run  is  over,  and  the  cupola  is  to  be  cleaned, 
the  prop  is  knocked  out,  the  doors  swing  down,  and 
the  sand  bed,  with  what  remains  of  the  charge,  drops 
to  the  floor  and  is  cleaned  away. 

Just  above  the  bottom  of  the  melting  chamber  is  a 
large  opening  called  the  breast,  filled  with  fire-clay, 
and  through  this  is  a  smaller  one,  E,  called  the  tap 
hole,  which  is  used  in  drawing  off  the  molten  metal. 
This  is  closed  by  a  plug  of  fire-clay  while  the  charge 
is  being  held  in  the  cupola.  Wheii  it  is  drawn  off, 
the  plug  is  removed  and  a  spout  lined  with  a  fire- 
sand  mixture  carries  the  stream  of  metal  to  the  bull 
ladle.  Above  the  level  of  the  tap  hole  and  on  the 
opposite  side  is  another  hole,  F,  termed  the  slag  hole, 
which  is  used  to  draw  off  the  slag  which  floats  at  the 
top  of  the  molten  metal.  Several  inches  above  the 
slag  hole  are  a  series  of  large  openings,  G,  called 
tuyeres,  extending  all  around  the  melting  chamber, 


Charging    .  ■ » 
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FIG.  9.      SECTION  OF  A  CUPOLA 
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THE  MECHANICAL  EQUIPMENT 


which  connect  the  melting  chamber  with  the  wind 
box  which  surrounds  it.  These  openings,  which  are 
usually  oblong,  direct  the  air  blast  into  the  fuel  bed. 
Peep-holes  in  the  outer  side  of  the  wind  box  opposite 
the  tuyeres  enable  the  melter  to  look  directly  into  the 
furnace.  The  height  of  the  tuyeres  above  the  bed 
varies  with  the  class  of  work.  Where  the  metal  is 
being  drawn  off  continually  they  may  be  as  low  as 
8  or  10  inches  above  the  sand  bed.  For  large  cast- 
ings it  is  necessary  to  collect  a  large  body  of  metal 
in  the  cupola  and  the  tuyeres  must  be  higher.  For 
the  largest  work  they  may  be  five  or  six  feet  up. 

The  air  blast  through  the  tuyeres  is  furnished  by 
fan  or  pressure  blowers,  and  the  quantity  of  air 
handled  is  very  large,  as  it  takes  about  30,000  cubic 
feet  of  air  to  melt  one  ton  of  iron.  The  table,  page 
69,  gives  the  average  melting  rate  per  hour  for  the 
various  sizes.  In  large  cupolas  there  are  two  sets 
of  tuyeres,  the  upper  row  provides  for  the  loss  of 
wind  should  the  lower  row  become  partially  clogged 
by  slag.  The  fuel  bed  should  extend  above  the  top 
of  these.  The  upper  tuyeres  have  a  smaller  area 
than  the  lower  as  they  are  intended  to  give  only  extra 
air  to  burn  the  cupola  gases  and  not  to  start  a  new 
melting  zone.  The  combined  cross-sectional  area  of 
the  lower  tuyeres  runs  from  one-fifth  of  that  of  the 
cupola  area  for  small  cupolas  down  to  one-tenth  on 
large  ones.  The  melting  zone  ranges  from  about  one 
foot  to  four  feet  above  the  tuyeres.  The  fire-brick 
lining  is  supported  at  various  heights  by  rings,  L, 
riveted  to  the  inside  of  the  shell.  This  permits  the 
separate  renewal  of  the  lining  around  the  melting 


MELTING,  POURING,  (LEANING  69 

zone,  where  the  wear  is  most  rapid,  without  disturb- 
mg  the  balance  of  the  lining. 

At  a  considerable  height  above  the  tuyeres  is  the 
charging  door  through  which  iron  and  fuel  are 
charged  m  alternate  layers.  The  width  of  the  charg- 
mg  door  for  various  sized  cupolas  is  given  in  the 
accompanying  table. 


General  Dimensions  of  Cupolas 


Capacity 
in 

tons 

per 

hour 


Ito 

3  to 

6  to 

9  to  10 
12  toll 
18  to  21 
24  to  27 


1 
2 
5 

7 


Inside 
diam- 
eter 
of 
lining 

Inches 


23 
27 
32 
42 
48 
60 
72 
84 


Diam- 
eter 
of 
Shell 


Inches 


Thickness  of 
Lining 


Below 
Charg- 
ing 
Door 
Inches 


32 
36 
46 
56 
66 
78 
90 
102 


4K 

4^ 

7 

7 

9 

9 

9 

9 


Above 
Charg- 
ing 
Door 
Inches 


Charging  Doors 


4K 
4^ 

4^ 


No. 


1 
1 
1 
1 
2 
2 
2 
2 


Height 
Inches 


Width 
Inches 


16 
20 
24 
27 
27 
27 
27 
27 


16 
20 
24 
30 
30 
36 
36 
36 


The  efficiency  of  the  cupola  type  of  furnace  is  very 
^igh,  as  the  melting  ratio  averages  about  one  pound 
ot  fuel  to  ten  of  iron.  This  arises  from  the  fact 
tliat  the  fuel  and  the  iron  are  intimately  in  contact. 
Ihis  close  contact  has  the  disadvantage  of  exposing 
the  iron  to  impurities,  such  as  sulphur,  which  may 
be  m  the  fuel,  and  therefore  the  cupola  furnace  can- 
not  be  used  for  many  of  the  higher  grades  of  cast- 


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70 


THE  MECHANICAL  EQUIPMENT 


ings.  Yet  on  account  of  its  cheapness  of  operation, 
its  convenience,  flexibility  of  control,  and  great  capac- 
ity, it  is  used  wherever  possible. 

The  Air  Furnace. — In  the  air  furnace,  shown  in 
Figure  10,  the  metal  is  charged  into  the  furnace 
through  a  charging  door  at  the  side;  the  fuel  is 
burned  in  a  separate  chamber,  A,  and  the  gases  are 
directed  over  a  bridge  wall  and  across  the  surface 
of  the  charge,  B,  which  lies  on  the  sand  bed,  C,  and 
are  carried  off  by  the  chimney  at  the  left.  As  the 
gases  in  their  passage  cling  to  the  top  of  the  furnace, 
the  metal  is  heated  more  by  radiation  from  the  in- 
candescent top  and  side  walls  than  by  direct  contact. 
Since  there  is  no  direct  contact  between  the  metal 
and  the  fuel,  fuel  impurities  in  the  latter  are  less 
troublesome  than  in  the  cupola,  and  a  better  qual- 


riG.  10.     SECTION  OF  AN  AIR  FURNACE 


MELTING,  POURING,  CLEANING  71 

ity  of  metal  is  obtained.  But  the  qualities  which  give 
the  air  furnace  a  purer  output  decrease  its  melting 
efficiency,  and  the  melting  ratio,  which  in  the  cupola 
will  run  from  one  of  fuel  to  eight  or  ten  of  metal,  in 
the  air  furnace  will  not  do  more  than  one  to  four. 
It  will,  however,  give  a  large  amount  of  high-grade 
metal  at  one  tap,  and  heavy  pieces  of  scrap  may  be 
used  which  are  difficult  to  handle  in  the  cupola. 

Open-Hearth  Furnace—The  open-hearth  furnace  is 
used  principally  for  melting  steel,  and,  to  some  extent, 
malleable  iron.    It  is  somewhat  similar  to  the  air  fur- 
nace except  that  it  has  two  gas  chambers,  A  and  A' 
and  two  chambers,  C  C  (Figure  11),  so  arranged  that 
the  direction  of  the   flame  can   be  reversed.     The 
checkered  brick-work  in  C  and  C  is  used  for  pre- 
heating the  air  so  that  it  enters  the  furnace  at  nearly 
1000  degrees  Fahrenheit.    This  furnace  gives  a  high- 
grade  product  and  has  a  heating  ratio  of  about  one 
to  SIX     By-product  or  producer  gas  is  generally  used 
as  tueL    The  gas  from  the  chamber.  A,  and  heated  air 
trom  C  unite  as  they  enter  the  furnace,  pass  over 
the   top   of  the   charge,   B,   and   then   out   through 
checkered  brickwork,  C,  which  absorbs  a  large  part 
of  the   remaining   heat.     When   the   gases   are   re- 
versed,  the  checkerwork,  C,  takes  up  the  pre-heat- 
ing  and  the  waste  gases  heat   the  brickwork,   C 
on  the  other  side  which  was  cooled  down  during  the 
previous  run.    The  direction  of  the  gases  is  reversed 
about  three  times,  an  hour. 

Oil  or  Gas  Furnaces—Figure  12  shows  an  oil  fur- 
nace of  the  type  used  in  a  brass  foundry.  These  are 
mounted  on  trunnions  to  permit  tilting  and  pouring 


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THE  MECHANICAL  EQUIPMENT 


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FIG.    11.      DIAGRAMMATIC   VIEW  OF   OPEN-HEARTH   FURNACE 

WITH  REGENERATORS 

and  the  fuel  is  supplied  through  one  of  the  trunnions 
at  one  end.  The  flame  plays  across  the  charge  and 
out  at  the  top.  The  metal  to  be  charged  is  first  laid 
on  top  of  the  furnace  while  the  fire  is  on,  where  it  is 
gradually  warmed  and  finally  is  pushed  into  the 
chamber  as  required.  When  oil  is  used  for  the  fuel, 
it  may  be  fuel  oil,  crude  oil,  distillate,  or  kerosene. 
Gas  may  be  used  in  the  form  of  natural  gas,  water 
gas,  or  city  gas.  Producer  gas  is  not  suitable,  since 
it  is  too  low  in  calorific  value  to  maintain  the  temper- 
atures required.  The  capacity  of  these  furnaces  var- 
ies from  500  to  1250  pounds  at  a  charge,  and  about 
1%  to  3  gallons  of  oil  are  required  to  melt  100  pounds 
of  steel. 


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THE  MECHANICAL  EQUIPMENT 


Crucible  Furnace. — The  crucible  furnace  is  shown 
in  Figure  13.  It  is  used  chiefly  for  melting  small 
special  mixtures  in  brass  foundries.  The  metal  does 
not  come  into  direct  contact  with  the  fuel  but  is 
placed  in  refractory  crucibles  which  are  covered  and 
set  in  the  furnace.  Graphite  is  the  principal  ingredi- 
ent used  in  the  construction  of  the  crucibles,  bonded 
with  fire  clay,  as  they  must  be  strong  and  tough  even 
at  a  high  temperature.  They  should  be  brought 
slowly  to  a  red  heat  before  using,  and  the  charge 
should  be  carefully  packed,  in  order  to  allow  expan- 
sion of  the  metals  inside  before  they  melt,  otherwise 
the  crucible  may  break.    The  fuel  may  be  hard  coal 


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JIG.   13.      CRUCIBLE  FURNACE  FOR   MELTING   BRASS 


MELTING,  POURING,  CLEANING  76 

or  coke,  sometimes  gas  or  oil.  When  the  charge  is 
melted,  the  crucibles  are  lifted  out  by  means  of  tongs 
and  emptied  into  serving  ladles.  Closed  crucibles 
are  used  in  brass  foundries  because  alloy  metals,  es- 
pecially zinc  and  tin,  burn  if  exposed  to  the  air  while 
melting.  If  the  casting  is  so  large  that  one  crucible 
Will  not  suffice,  several  furnaces  must  be  used  and 
their  crucibles  discharged  into  one  large  ladle. 

Electric  Furnace.— Electric  furnaces  are  very  ex- 
pensive in  operation  and  little  used  except  for  making 
high-grade  steel  in  small  quantities.  Their  advan- 
tage  lies  in  the  accurate  control  of  the  chemical  con- 
stituents during  melting. 

Ladles.— The  molten  metal  is  transported  from  the 
furnace  to  the  mold  in  ladles.    These  range  in  capac- 
ity from  25  or  30  pounds  up  to  60  tons.     The  large 
ladle  that  is  located  permanently  at  a  cupola  into 
which  the  spout  discharges  is  called  the  bull  ladle.    It 
is  mounted  on  trunnions  and  is  tilted  to  pour  metal 
into  serving  ladles  which  are  brought  to  it.    Serving 
ladles  may  be  carried  by  crane,  overhead  trolley,  or 
by  hand.    Hand  ladles  may  be  single  or  double,  de- 
pending upon  whether  they  are  carried  by  one  or 
two  men.    All  ladles  are  made  of  metal,  with  a  re- 
fractory  lining  to  protect  them  from  burning.     The 
smaller  ladles  are  provided  with  a  lip  or  spout  from 
which  the  metal  is  poured.    Large  ladles  are  carried 
by  cranes  and  are  controlled  by  gears  to  facilitate 
pouring   and   to   prevent   accidents   from   too   rapid 
turning.      Very    large    ladles,    such    as    those    used 
m  steel  foundries,  are  not  turned  in  pouring  but  are 
provided  with  u  tap  hole  in  the  bottom.    The  lining 


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76 


THE  MECHANICAL  EQUIPMENT 


in  small  and  medium  sized  ladles  will  vary  from 
three-fourths  inch  to  two  inches  in  thickness  accord- 
ing to  size.  Large  ones  are  lined,  first,  with  fire  brick 
and  then  daubed  with  a  clay  mixture  similar  to  a 
cupola  lining.  Ladles  must  be  well  dried  before  using. 

Pouring. — In  pouring  the  molds  care  must  first  be 
taken  to  skim  off  the  slag.  With  large  ladles,  this 
should  be  done  before  leaving  the  cupola  and  again  as 
the  metal  is  poured.  A  skimmer,  which  is  a  long 
iron  rod,  is  used  for  this  purpose;  the  end  of  it  rests 
across  the  top  of  the  ladle  near  the  pouring  spout  to 
hold  back  the  slag  while  the  metal  runs  free. 

Great  skill  is  required  in  pouring  molds,  as  the 
speed  with  which  the  metal  should  be  poured  varies 
with  the  character  of  the  work.  It  should  be  done 
slow  enough  to  allow  the  gases  to  escape  and  yet  fast 
enough  to  keep  the  metal  from  chilling  in  the  mold 
and  forming  ** cold-shuts,''  as  they  are  called.  Care 
must  be  exercised  to  keep  the  stream  steady  and  not 
to  ** spill"  into  the  mold;  the  basin  at  the  gate  of  the 
mold  should  be  just  kept  full.  It  is  of  vital  impor- 
tance that  the  pourer  gauge  correctly  the  amount  of 
metal  required,  for  if  he  has  not  enough  metal  in  his 
ladle  to  fill  the  mold  and  must  use  the  second  one,  he 
is  practically  certain  to  lose  his  casting.  Any  metal 
remaining  after  pouring  should  not  be  allowed  to  chill 
or  freeze  in  the  ladle,  but  should  be  poured  into  a 
larger  ladle  or  emptied  on  the  floor.  Pig  beds  are 
usually  provided  near  the  cupola  for  this  purpose. 

Defects  of  Castings.— The  accompanying  table 
shows  the  principal  defects  of  castings,  with  their 
causes  and  cures: 


MELTING,  POUEING,  CLEANING  77 

Poured  Short: 

^TolTnoTmieV^  """^^^  '"^  *^'  ^^^^  misjudged  and  the 
Cure— Have  enough  metal. 
Blow  Holes: 

^Ztr^^''/  P^^^^ted  in  the  mold,  sand  packed  too 

tight   sand  too  wet,  or  poor  venting. 
Lure— Provide  adequate  venting. 

Cold  Shut: 

Cause-Two   streams   of   metal   meeting   in   the   mold 

which  are  too  cold  to  fuse  together 
Cure— Use  hotter  metal  or  have  a  thicker  section. 
Sand  Holes: 

Cause—Loose  sand  washing  into  the  cavity  and  fusing 
into  the  metal.    Too  little  facing  ^ 

Cure— Have  a  stronger  mold,  use  more  facing  If 
necessary,  use  dry  sand  mold.  ^' 

Lifts: 

Cure— Weighting  or  clamping  the  cope. 
Shifts : 

^T^^A^  """"P^  ^'""^  misplaced  sidewise  with  respect 

Cure-Proper  registering  between  cope  and  draff 
Core  Shifts:  ^' 

cT^^'"'^^  breaking  or  becoming  misplaced. 
Cure— Stronger  cores  and  more  careful  setting. 

^''^'  c2S)  r"""'*^'^'  projections  on  the  surf  ace '  of  the 
Cause— Mold  washing  off  and  being  carried  awav 
Cure-Stronger  mold,  better  rammld,  and  mo^'^^acing. 

Swells  (Bulges  in  the  casting)  : 
Cause — Too  soft  ramming. 
Cure — Proper  ramming. 


78 


THE  MECHANICAL  EQUIPMENT 


M-    I 


Shrinkage  (cracks) : 

Cause — Unequal  cooling  or  mold  too  firm  to  give  as  the 

metal  cools. 
Cure — Re-design  of  the  part  or  lighter  packing  in  the 

mold. 

Warping : 

Cause — Pattern  may  have  warped;  casting  may  have 
lugs  on  one  side  retarding  the  shrinkage,  or  sand  may 
be  packed  harder  on  one  side  than  on  the  other. 

Cure — Correcting  the  pattern  or  relief  of  the  strain. 

Cleaning. — After  th<^  castings  are  poured  sufficient 
time  should  be  allowed  for  the  metal  to  set.  In  small 
castings  this  may  be  a  matter  of  a  few  moments;  in 
very  large  ones,  it  may  take  a  week  or  even  more. 
If  castings  are  knocked  out  too  soon,  shrinkage 
strains  and  cracks  result.  When  the  castings  are 
removed  from  the  sand,  the  gates  are  broken  off  and 
turned  into  the  scrap  pile  for  remelting  and  the  cast- 
ings are  collected  and  carried  to  the  cleaning  room 
as  molding  floor  space  is  too  valuable  to  be  tied  up 
with  work  which  can  be  done  elsewhere.  The  cores 
and  core  irons  are  dug  out  and  the  fins  (thin  sheets 
of  metal  which  seep  out  between  the  cope  and  drag) 
are  chipped  off.  In  large  work  much  of  the  cleaning 
is  done  by  hand,  but  it  is  greatly  facilitated  by  the 
use  of  air  chipping-hammers,  and  for  very  large  work, 
especially  large  steel  castings,  the  oxy-acetylene  flame 
or  the  electric  torch  is  used  to  cut  off  risers,  etc. 

Tumbling. — Tumbling  is  the  most  effective  way  of 
cleaning  small  castings  which  are  fairly  uniform  in 
size  and,  in  general,  not  over  50  to  100  pounds  in 
weight.  Tumbling  barrels  are  made  of  steel  plate 
and  lined  with  chilled-iron  bars  to  protect  the  shell. 


MELTING,  POURING,  CLEANING  79 

Tlie  bearings  of  these  barrels  are  sometimes  hollow 
and  connected  with  an  exhaust  system  to  draw  off  the 
dust.    As  the  barrels  revolve,  the  castings  tumble 

ZZu  Z'"'  '^T'"^  '^'^  °*^«'-  •"  t^«°ty  minutes 
or  half  an  hour.  To  facilitate  the  cleaning,  shot  iron 
and  hardened  stars  are  thrown  in  and  revolved  with 
the  castings     When  removed  from  the  barrel  iron 

fact "^F  1  "T  ^  "'"""'  ^•""^t^'  grey-colored  sur- 
face From  he  tumbling  barrels  the  castings  may 
be  taken  to  the  dry  emery  wheels  for  grinding  off 

i'lCJiIing.— Where  much  machining  is  to  be  done 
the  presence  of  sand  and  scale  on  the  surLe  of  the 
casting  plays  havoc  with  the  cutting  tools.     Such 
par  leles  may  be  removed  by  the  proc:ss  of  pickUng 
This    consists    in    washing    the    castings    in    dilute 

r  ati^f^^  f'r'^f''  ^'''^  ^""^^'^  -ith  watert 
a  ratio  of  1  to  8  or  1  to  10.  They  are  left  in  this 
bath  long  enough  to  cut  out  the  sand  and  the  hid 
skin  of  iron  oxide,  which  is  formed  when  the  iron 

the  casting.    After  removal  from  the  pickling  bath 

enough  to  heat  them  so  that  they  will  dry  ranidlv 
Sand  Blast-Small  and  delicate  castings  whLh  can 

sand  blast.  Sharp,  clean  sand  is  blown  against  the 
surface  by  compressed  air  at  about  10  pounds  pres! 
ure,  giving  the  casting  a  beautiful  finish  The  work 
requires  a  considerable  apparatus  and  invoir  a 
separate  room.  The  operators  must  be  protic  Id  bv 
helmets  and  supplied  with  fresh  air  througla  Ce 


p'i 


V4 

'hi 


>  I 


I 


pf 


A 


CHAPTER  VII 
FOKGING  METHODS 

Hand  Work.— Many  metals  may  be  formed  or 
shaped  either  hot  or  cold,  but  the  term  forging  is 
confined  to  the  working  of  heated  metal  under  blows 
or  heavy  pressure.  The  forming  of  cold  metal  by 
press  work,  or  cold  stamping,  requires  more  power, 
because  of  the  higher  resistance  of  the  metal  to  a 
change  of  shape;  but  it  is  more  accurate  than  hot 
work,  as  the  uncertainties  of  shrinkage  are  elimi- 
nated, and  is  faster  than  forging  because  the  work 
may  be  manipulated  by  hand  instead  of  by  tongs. 
Pressing  and  stamping  machines  form  an  entirely 
different  class  from  those  used  with  hot  work  and  are 
located  in  a  different  department.  Hence,  hot  work, 
or  forging,  only  will  be  taken  up  in  this  chapter. 

In  the  past  fifty  years  the  work  of  the  forge  shop 
has  been  undergoing  gradual  changes.  Hand 
methods  have  been  supplemented  by  forging  ma- 
chinery, and  the  field  has  extended  in  two  directions: 
Steam  hammers  and  hydraulic  presses  have  permitted 
an  enormous  increase  in  the  size  of  forgings,  while 
drop  hammers  and  the  various  other  forms  of  power 
hammers  have  introduced  manufacturing  methods  in 
a  refined  form.  On  the  other  hand,  the  foundry  has 
been  cutting  into  the  field  of  the  forge  shop  through 

80 


FORGING  METHODS     .  ffl 

the  increasing  production  of  steel  and  malleable  iron 
castings  now  used  for  many  articles  which  formerly 
were  forgings. 

The  principal  materials  which  are  forged  com- 
mercially are  machinery  steel,  tool  steel,  wrought 
iron,  bronze,  copper,  and  aluminum.  Bough  stock 
IS  usually  m  the  form  of  merchant  bars  for  small  and 
medium  sized  work  and  of  billets  for  large  forgings 

follows  •^'''''''  '^^^^''^^  ""^  ^'"''^''^  ""^^  ^^  ^^^^P^^  ^' 

Hand  work 

Welding 

Steam  hammer  work 

Drop  forging  and  power  hammer  work 

Heading  and  upsetting 

Hydraulic  press  work 

Rolling 

Drawing 

Extrusion  work 

Pipe  bending. 

Hand  forging  will  always  have  its  place  for  all 
small  and  special  work,  for  making  the  special  cut- 
ing  tools  used  in  every  machine  shop,  and  for  the 
Hand  tools,  special  rivets,  bolts,  etc.,  on  large  en- 
gmeenng  operations.  But  little  tool  equipment  is  re- 
qmred  which  can  be  easily  moved  from  place  to 

The  Forge.— The  equipment  for  hand  forging  in- 
volves a  forge  fire.  This  may  be  either  a  pemanent 
Sr  '?    ?'  ''^''  °^  blacksmith  shops  in  manufac- 

anvi!  ^         '  "'■  ,P*'J*^*'^^  '"  ^^^^  "  ™^y  be  set  up 
anywhere-on  a  platform,  on  an  engineering  structure 


mm 


.1* 


\y, 


w 


82 


THE  MECHANICAL  EQUIPMENT 


tinder  erection,  or  in  a  shanty  by  a  railroad  track. 
The  usual  fuel  for  small  fires  is  soft  coal,  but  occa- 
sionally  charcoal,   coke,   or   hard   coal   is   used.    It 
should*^  break    easily    and    burn    freely    with    little 
clinker.    The  necessary  air  is  furnished  from  beneath 
through  tuyeres.    In  permanent  forges  the  tuyeres 
are  connected  with  a  general  blower  system  serving 
the   forge    shop.    For    portable   forges    the    bellows 
used    from    time   immemorial    are    giving    place    to 
small,    hand-operated,     rotary     blowers.    The     fires 
should  be  kept  as  small  as  possible,  but  should  be 
deep  enough  to  make  sure  that  the  air  blast  is  dis- 
tributed evenly  through  the  coal  and  does  not  strike 
open  spots.    This  is  necessary  for  even  heating,  for 
the  hottest  part   of  the  fire  follows   the  blast.    A 
blacksmith  will  often  stir  the  bar  he  is  heating  to 
loosen  it  from  the  coals  and  to  allow  the  air  freer 
access  to  the  coal  immediately  around  it.    Fuel  is 
usually  added  to  the  fire  at  the  side  and  is  gradually 
worked  in  toward  the  center  of  heating.     Fires  may 
be  either  oxidizing  or  reducing,  according  as  there 
is  or  is  not  an  excess  supply  of  oxygen  through  the 
air  blast.    An  oxidizing  fire  should  be  avoided,  as 
it   produces   scale   or   iron   oxide   which   wastes   the 
metal  and  interferes  with  forging.    When  the  right 
amount  of  air  is  admitted  the  iron  will  come  out 
bright  and  clean. 

For  permanent  forges,  such  as  are  used  for  tool 
dressing  in  machine  shops,  gas  or  oil  are  the  best 
fuels  as  they  are  cleaner  and  afford  easy  and  accurate 
control  of  the  heat.  They  are  generally  used  on  drop 
forging   and   large  work   for   similar   reasons.     Care 


FORGING  METHODS  83 

must  be  used  to  heat  large  forges  slowly  and  uni- 
formly  and  to  avoid  oxidation.  If  the  surface  is  too 
hot  and  the  interior  too  cold,  transverse  cracks  will 
appear  on  the  surface  of  the  work  being  forged.    If 

tiLThp  7  -r  T''''^  "^^  '^'  ^^«id^  i'  hotter 
than   the   outside,   longitudinal   cracks   will   appear 

Steel  should  be  forged  with  as  few  heats  a  poSle 
There  is  more  danger  of  injuring  the  stock  by  work- 

Sel  :Z  ^^  r^'  '^""  "^^"  "  -  --heated 
Steel  should  not  be  allowed  to  remain  in  the  for^e 

fire  longer  than  is  necessary,  or  the  material  wi  1  re' 

carbonize.    For  very  large  work  a  reverberatory  or 

2  f™  "  T^  "'^^'  ^^  ^^"^^^^*  similar  to  the 
air   furnace    shown    in    Figure    10.     These    are    not 

economical  of  fuel,  but  they  provide  means  for  S^e 

uniform  heating  of  large  work.     The  billets,  or  ma! 

the'nd'  }T\  '"  '""''^''^  ^^-"^h  -^-r  at 
rom'thV^l/''  .''''i"^  "  '^^^  ^^  ^^^  -d-tion 

The  fir        I   ^""^  f  ^''   "^   *^^   ^^^^^^^   chamber. 
J  he  fuel  most  used  for  these  furnaces  is  soft  bitu- 

«s  coal,  and  the  furnaces  are  used  in  connecdl„ 

Ce  Si:;.'""' '"""°™ "—  "■•  "»*  - 

cat"n^*  r'^^'"^  ^''  '"^•^'"'*  *^  shrinkage,  as  in  the 

T:\t:Ttc'^^'  TT  "^^'  ^^^--ssar; 

Tools.— The  important  tools  in  hand  work  are  th^ 

-5L  aboul  n/    '''"i  ''T""''  '•'"^  ^"<*  ^  head 
g'ung  about  11/2  pounds.    Figure  14  shows  some 


.  > 


84 


THE  MECHANICAL  EQUIPMENT 


of  the  more  common  forms  of  heads.  The  eye  of  the 
head  is  usually  set  so  that  the  greater  weight  is  on 
the  face  side,  as  heavier  and  more  accurate  blows 
may  be  struck  than  if  the  weight  were  evenly 
balanced.  Sledges,  which  are  heavy  hammers  used 
by  a  helper  and  swung  with  both  hands,  vary  in 
weight  from  5  to  20  pounds;  they  average  about  12  or 
15  pounds. 

The  first  requirement  of  a  blacksmith's  anvil  is 
weight.  It  should  be  able  to  absorb  its  own  shocks, 
and  any  anvil  which  has  to  be  braced  is  practically 
useless.  The  next  requirement  is  that  it  have  a  hard 
face,  for  it  must  be  able  to  withstand  the  roughest 
kind  of  use.  Modern  anvils  usually  have  a  wrought 
iron  body  to  which  is  welded  a  hardened  steel  face. 
The  well-known  shape  of  an  anvil  is  a  gradual  de- 
velopment through  miany  generations.  At  one  end  is 
a  tapering  horn,  at  the  other  a  wedge-shaped  projec- 
tion having  a  square  hole  into  which  auxiliary  tools 
may  be  set.  It  is  mounted  on  a  heavy  wooden  block, 
about  20  inches  high,  to  give  it  a  firm  but  elastic 
foundation,  and  its  weight  usually  runs  from  150  to 
300  pounds. 

The  tongs,  some  varieties  of  which  are  shown  in 
Figure  14,  are  made  of  steel  and  vary  in  size  and 
shape  to  meet  the  needs  of  the  various  articles 
handled.  The  handles  are  long  and  often  are  pro- 
vided with  a  slip  ring  which  can  be  slid  along  to 
clamp  the  tongs  upon  the  work. 

Some  other  auxiliary  tools  are  set  hammers  for 
working  into  corners  and  narrow  places,  flatters  for 
smoothing  out  high   surfaces,   swages   for  finishing 


FORGING  METHODS 


m 


TOP       BOTTOM       HOT  CUTTER  BOTTOM         TOP 
FULLER  FULLER  SWAGE,     SWA6E 


COUNTERSINK 


CAPE   CHISEL 


CHIPPING   CHISEL 


ROUND 
■PUNCH 


t^ 


STRAIGHT  LIP  TONGS 

a 


HARDIE 


GAD  TONGS 


SINGLE  PICK-UP  TONGS 


CENTER  PUNCH 


BAND   TONGS 


SQUARE 
FLATTER 


ANGLE  JAW 


2*= 


RIVET   TONGS 
^     '"^   HOOK  AND  HANDLE  RULE 


SET  HAMMER 


ENGLISH  PATTERN        SLEDGE 


BALL  PEIN 
HAMMER 


AMERICAN  PATTERN 


FIG.   14.      HAND  FORGING  TOOLS 


J 


I,  ;,„il 


I    H 


i 


71        ,  'i 


'■l-\ 


86 


THE  MECHANICAL  EQUIPMENT 


i 


round  and  convex  surfaces,  fullers  for  working 
grooves  or  hollows  into  shape,  swage  blocks  which 
contain  holes  of  various  sizes  and  shapes,  steel 
calipers  for  measuring  the  work,  and  the  necessary 

fire  tools. 

Operations.— The  operations  of  hand  forging  cover 
almost  every  type  of  forging  work.  The  principal 
ones  are  drawing,  upsetting,  riveting,  bending,  shrink- 
ing, and  welding. 

Drawing  consists  of  hammering  the  piece  on  the 
side  and  rotating  it  at  the  same  time  between  each 
blow.  Under  the  influence  of  the  hammering  the 
metal  spreads  in  all  directions,  but  the  metal  forced 
sidewise  by  one  blow  is  driven  back  by  the  next, 
while  the  displacement  of  the  metal  endwise  is  unob- 
structed. The  effect  is  to  work  the  metal  longitudi- 
nally, and  a  short  piece  of  large  diameter  may  be 
drawn  out  into  a  long  one  of  small  section. 

Upsetting  is  the  reverse  of  drawing;  a  long,  thin 
piece  is  forged  from  the  end  and  spread  out  sidewise 
to  form  a  head  (as  in  the  case  of  bolts),  or  sometimes 
a  bulge  in  the  middle. 

Eiveting  is  a  special  form  of  upsetting  where  heads 
are  formed  in  place  on  rivets  to  secure  two  pieces  of 

metal  together. 

Bending,  which  needs  no  explanation,  is  usually 
done  over  the  edge  of  the  anvil  or  around  the  horn. 

Shrinking  is  the  setting  of  forged  rings  tightly  on  a 
solid  core  or  bar.  The  ring  is  forged  hot  to  a  sliding 
fit,  slipped  over  the  core,  and  allowed  to  cool.  The 
shrinkage  causes  the  ring  to  grip  the  core  with  tre- 
mendous force. 


FORGING  METHODS  gl 

Welding.-Welding  is  the  process  of  joining  two 
pieces  of  heated  iron  or  steel  by  placing  them  together 
and  hammenng  the  joint.  It  is  one  of  the  mosf  skil- 
ful branches  of  the  blacksmith's  art.  The  heating 
must  be  done  evenly  and  cleanly  in  a  reducing  firel 
too  high  a  temperature  is  sure  to  form  scale,  and  at 
too  low  a  heat  the  metal  will  not  weld.  The  proper 
s3  "VT^^^^^^^^V^^^^tituting  what  the  black- 
smith calls  -welding  heat,-  is  therefore  narrow 

evil  of  welding     It  may  be  formed  in  the  fire  and  will 
collect  on  the  heated  metal  from  contact  with  the  air 
The  process  of  welding  is  a  mechanical  one,  and  there 
is  no  direct  chemical  action.     It  is  facilitated  by  the 

TA       ^^7'  Tf^  '^^^  "^  ^^^^^  ««  the  surface 
to  be  welded  which  unites  with  the  scale  and  forms  a 

slag  that  melts  at  less  than  welding  heat  and  is  forced 
out  m  the  hammering.  In  -scarfing,-  or  preparing 
the  pieces  for  welding,  the  surfaces  to  be  joined 
should  be  convex  so  that  they  will  touch  first  in  the 
center.  This  facilitates  forcing  out  the  slag.  If  the 
surtaces  are  concave,  some  of  the  slag  is  likely  to  be 
pocketed  in  the  joint  and  cause  an  imperfect  weld 

Dissimilar  metals,  such  as  steel  and  wrought  iron  * 
or  tool  and  machinery  steels,  may  be  welded  together! 
but  they  require  skilful  handling  as  the  welding  heats 
ot  the  two  metals  are  not  the  same.  Imperfect  welds 
21  ri /.''•'^ Fr!'''"  '^"*^'*'  insufficient  hammering, 
ttt  r  V".  '^'  •*'^^''  ^^"^  insufficient  fluxing,  so 
hat  the  scale  is  not  all  cared  for;  from  too  high  or 

Whe  n.         \  '^^    ^''"^    ™P"^^*^^^    ^^    the   metal. 
>Vhere  the  carbon  in  steel  runs  over  1.1  per  cent  it  is 


Ml' 


(.  'U 


^ 


.. 


I 


88 


THE  MECHANICAL  EQUIPMENT 


difficult  to  make  a  weld;  and  cast  iron  which  contains 
2  per  cent  or  3  per  cent  of  carbon  cannot  be  welded 
at  all  by  the  ordinary  methods.  Silicon,  phosphorus, 
sulphur,  and  manganese  all  lower  the  welding  quali- 
ties of  iron.  The  purest  and  softest  steels  weld  the 
best.  For  these  reasons  the  efficiency  of  a  weld  is 
uncertain;  it  will  average  from  70  per  cent  to  80  per 
cent  but  may  be  as  low  as  50  per  cent.  Welds  made 
with  a  steam  hammer  are  stronger  than  hand  welds 
of  the  same  size.  The  art  of  welding  has  received 
enormous  development  in  recent  years  and  methods 
other  than  the  use  of  a  forge  fire  and  hammering  will 
be  discussed  later. 

Steam  Hammer  Work. — Steam  hammer  work  is  a 
development  from  hand  forging  and  differs  from  it 
only  in  the  size  of  the  work  handled.  Three  types  of 
steam  hammers  are  used:  one  where  the  hammer  is 
lifted  by  steam  and  drops  of  its  own  weight;  one 
where  exhaust  steam  is  admitted  above  the  piston 
and  by  its  expansion  increases  the  force  of  the  blow, 
and  a  third  where  live  steam  is  used  above  the  piston 
throughout  the  downward  stroke. 

The  first  class  is  used  for  very  large  work  and  the 
weight  of  the  hammer  ranges  from  25  to  125  tons. 
Its  disadvantage  lies  in  the  fact  that  the  height  of  the 
piston  in  the  cylinder  from  the  lower  cylinder  head 
varies  with  the  thickness  of  the  work  and  forms  a 
clearance  space  which  must  be  filled  with  live  steam. 
In  the  second  class  the  consumption  of  steam  is  less, 
the  force  of  blow  is  greater  and  a  larger  number  of 
blows  are  given  in  a  minute,  but  the  reliability  of 
operation    is    more    or    less    uncertain.      The   third 


FORGING  METHODS  8!l 

class  IS  the  most  widely  used:  here  the  weight  of 

)TrVT^  ^'"^  "^'  *"  ^^  ^^^«^  the  number  and 

orce  of  blows  can  be  regulated  by  throttling  the 

steam,  and  the  control  is  such  that  the  weight  of 

the  hammer  only  may  be  used  for  light  blows,  while 

^P^w.  T  '^!f  ^''  *^'  ^^"^^^^  ^^^^«-  These  ham. 
mers  work  rapidly  and  are  provided  with  automatic 
reversmg  gears,  so  that  as  many  as  350  blows  a 
mmute  may  be  obtained. 

The  frames  of  steam  hammers  may  be  single  or 
l'?he^i^""'  15  and  16).  The  douWe  frame!  used 
on  the  larger  sizes  are  stronger  than  the  single  frame 

In  boirf'"'  "I'T'  "'^"'  ^^^  ^-"  -  -^trict'd! 
In  both  types  the  hammer  head  usually  is  guided  by 

aTXv  ;^'"in  '^^'  ^''^-    ^P^^  frame  Lmmers! 
as    hey  are  called,  are  used  for  certain  classes  of 

work  where  slides  would  be  troublesome     In  5e„,t 

large  piston  rod  and  small  head  in  one  piece  le 

rrarsr  ^"*'  '"■ »" '-  -- «» •"« 

The  anvil  of  a  steam  hammer  is  a  large  casting 

ftm  tre  re^^^^^^^^^^^^   ™'  ^^  ^  -P-^te  foundS 
trom  the  rest  of  the  hammer  to  lessen  the  shock  on 

he  working  parts.    In  good  practice  the  weight  of 

hltTthfh'^'  '^  r  ^^  ^^^^  '^^  -  twelv^tim 
hat  of  the  hammer  head;  the  heavier  the  better  for 

^ImT^  ''  -f'^  '™^^  ^^  increased  as '  the 
^v  eight  of  the  anvil  is  increased. 

requiredt  'tf  X^T'"'''^  '""^  ^'^  ^^  hammer 
inlT  .!.  ™"'*'P'''  *^^  ''^^s  section,  in  square 
■nches  of  the  work  to  be  forged  by  80  for  steeJ  and 
by  60  for  wrought  iron.    For  example,  a  steel  forgtng 


lu'.'l 


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i')i 


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% 


t   ' 


90 


FOEGING  METHODS  91 

5  by  5  inches  would  call  for  a  2000-pound  hammer. 
The  question  is  often  asked,  "What  is  the  force  of  the 
blow?"  It  is  impossible  to  tell,  if  by  this  is  meant  the 
pressure  produced.    The  energy,  represented  by  the 
weight  and  velocity  of  the  moving  parts  as  they 
strike  the  work,  is  determinable;  but  the  pressure 
which  IS  exerted  varies  inversely  with  the  distance 
m  which  they  are  brought  to  rest  after  they  strike 
the  work.    Thus,  while  the  forging  is  hot  and  soft, 
the  hammer  sinks  into  the  metal  some  distance  and 
the  pressure  is  comparatively  low;  and  as  the  forging 
cools,  the  metal  grows  harder  and  the  pressure  in- 
creases  rapidly.    There  is,  therefore,  no  feasible  way 
of  rating  hammers  other  than  by  the  weight  of  their 
falling  parts. 

The  field  of  the  steam  hammer  is  that  of  general 
torging  on  large  and  special  pieces.    Sometimes  dies 
are  used,  but  if  so,  they  are  only  of  the  simplest 
character.    Steam  hammer  work  has  been  cut  into  in 
recent   years   from   two   directions.    The   hydrauUc 
press  IS  preferable  for  very  large  work,  as  it  produces 
sounder  forgings  and  has  th6  further  advantage  of 
quietness  of  action;  while  the  heavy  blows  of  a  large 
steam  hammer  may  often  cause  so  much  vibration  and 
noise  as  to  be  objectionable  to  an  entire  neighborhood. 
Ihe  other  restriction  of  field  comes  from  the  increas- 
ing use  of  steel  castings  which  do  away  with  the 
necessity  of  uncertain  welds' in  built-up  work,  such  as 
tne  side  frames  of  locomotives. 

Power  Hammers—Drop  hammers  are  confined  to 
small  and  medium  sized  work  and  are  used  where 
many  pieces  of  the  same  kind  are  needed.    Drop 


11  ■« 


!■ 


?■••::(• 


J'' ■^- 
■.J;.'..,  . 


f 


•M 


FUliUliNU  .METHODS  yj 

5  by  5  iiK-hcs  would  call  for  n  ^dOO-jioujid  liainmcr. 
The  riuostion  is  oltcn  askocl,  "Wliat  is  tlu-  l'o.v«.  of  the 
hiow?"  It  is  iini)()ssil)|,.  to  tell,  it  l)y  this  is  meant  the 
pressure  j.roduced.     The  energy,  represented  hv  the 
w<-islit   and   veloeity   of   tlie   moving   pai-fs   as"tliev 
Mrdvo  the  work,  is  determinable;  but   the  pressure 
yhieli  IS  exerted  varies  inversely  with  the  distance 
in  wjiieli  tliey  are  ])rought  to  rest  after  thev  strike 
the  woi'k.    TJius,  wliilo  tlio  forging  is  hot  and  soft, 
the  hammer  sinks  into  the  metal  some  distance  and 
the  pressure  is  comparatively  low;  and  as  the  forging 
cools,  the  metal  grows  liai-der  and  tlio  pressure  in- 
creases rapidly.     There  is,  therefore,  no  feasible  wav 
"I  rating  hammers  other  than  by  the  -n-eiglit  of  their 
i ailing  parts. 

The  tield  of  tlio  steam  liammer  is  that  of  general 
lorgmg  on  largv  and  special  pieces.    Sometimes  dies 
"'•<•  nsed,  but  if  so,  they  are  only  of  the  simplest 
'•liaracfer.    Steam  hammer  Avork  has  been  cut  into  in 
'•'■cent    years    from    two    dir(..-tions.    The    hvdraulic 
press  ,s  pivferable  for  very  large  Avork,  as  it  produces 
sounder-  lorgmgs  and  lias  the  further  advantage  of 
qmelness  of  action;  while  the  heavy  blows  of  a  large 
M.;ani  JiamnHu-  may  often  cause  so  much  vibration  and 
iioise  as  to  bo  objectionable  to  an  entire  neighborhood. 
I  he  other  restri<-tion  of  field  comes  from  the  increas- 
"IK  use  of  steel   castings  which  do  awav  with  the 
"'■cess.ty  of  uncertai.i  w<>lds  in  built-up  woric,  such  as 
liio  side  frames  of  locomotives. 

Power  Hammers.-l),op  hannuers  are  confined  to 
■"lall  and  medium  sized  work  and  are  used  where 
inany   pieces   of   the  same   kind   are   needed.    Drop 


92 


THE  MECHANICAL  EQUIPMENT 


forging  is  becoming  an  art  in  itself  and  is  so  im- 
portant that  it  will  be  taken  up  separately. 

Power  hammers  other  than  drop  hammers  are  used 
in  a  wide  variety  of  types.  The  oldest,  the  helve 
hammer,  now  largely  obsolete,  consists  of  an  oscillat- 
ing wooden  beam  pivoted  at  one  end  and  carrying  at 
the  free  end  the  upper  half  of  a  pair  of  dies,  the 
lower  half,  being  carried  in  an  anvil  below.  The 
beam  is  lifted  by  a  rotating  shaft  carrying  a  series 
of  cams,  each  of  which  raises  the  hammer  and  allows 
it  to  drop  suddenly.  This  type  has  been  used  from 
mediaeval  times.  The  modern  development  of  the 
helve  hammer  is  seen  in  the  Bradley  hammer.  Figure 
17.  In  this  the  beam  is  operated  by  a  swinging 
frame  driven  from  a  rotating  shaft.  Between  the 
frame  and  the  beam  rubber  cushions  are  interposed, 
the  effect  of  which  is  to  soften  the  action  on  the 
driving  mechanism  and  to  give  a  quick  blow. 

The  Beaudry  hammer,  Figure  18,  which  is  a  crank- 
operated  power  hammer,  is  also  widely  used.  The 
head  of  this  hammer  has  an  internal  curve  or  track. 
Two  steel  arms,  acting  as  springs,  carry  hardened 
rollers  which  bear  on  the  curved  surface  and  trans- 
mit the  power  from  the  rotating  shaft  to  the  hammer 
head.  The  action  gives  a  quick  stroke  and  allows 
a  rebound  the  instant  the  blow  is  made. 

Another  type  of  power  hammer  is  the  pneumatic 
hammer  operated  by  compressed  air  supplied  by  an 
air  compressor  integral  with  the  frame.  The  pur- 
pose in  all  of  these  types  of  hammers  is  to  give  a 
quick,  sharp  blow.  They  are  started  and  stopped  by 
a  foot  treadle:  by  varying  the  pressure  on  the  treadle 


93 


1  '* 

f^^^^ 

LiJ'J^^^^H 

v„:^'^^| 

i'^^'i^H 

1  '       I^^^^^^^^^H 

^n^^l 

-  .  ) 

^^^^Hi 

1)2 


THE  ME(  HANK  AL  KQl'IPMENT 


foruiii^'  is  1)tvomin.i»-  an  art  in  itscll'  and  is  so  im- 
portant that  it  will  he  taken  n|)  s('[)arat('ly. 

Power  hanuners  other  than  drop  hanuners  are  used 
in  a  wide  variety  of  tyi)es.  The  oldest,  tlie  helve 
lianuner,  now  largely  obsolete,  consists  of  an  oseillat- 
in.i;-  wooden  Leani  i)ivoted  at  one  end  and  ejirrying  at 
the  free  end  the  upper  half  of  a  pair  of  dies,  the 
lower  half  hein.i;-  carried  in  an  anvil  l)eh)W.  The 
heani  is  lirte(l  hy  a  rotating  shaft  carrying  a  series 
of  cams,  each  of  Avliich  raises  the  hammer  and  allows 
it  to  drop  suddenly.  This  type  has  heen  used  from 
mediaeval  times.  The  uiodern  development  of  tlie 
helve  hammer  is  seen  in  the  Bradley  hammer,  Figure 
17.  In  this  the  ])eam  is  operated  by  a  swinging 
frame  driven  from  a  rotating  shaft.  Between  the 
frame  and  the  l)eam  rul)l)er  cushions  are  interposed, 
the  elTect  of  which  is  to  soften  the  action  on  the 
driving  mechanism  and  to  give  a  ({uick  blow. 

The  Beaudry  hannner,  Figure  18,  which  is  a  crank- 
operated  j)ower  hannner,  is  also  widely  used.  The 
head  of  this  haiinnei-  has  an  int(Mnal  cui've  or  track. 
Two  steel  arms,  acting  as  s])rings,  carry  liardened 
rollers  which  beai'  on  the  curved  surface  and  trans- 
mit the  power  from  the  rotating  shaft  to  the  hammer 
head.  Tin*  action  gives  a  (piick  stroke  and  allows 
a  rebound  the  instant  the  blow  is  made. 

Another  ty])e  of  power  hammer  is  the  pneumatic 
hannner  operated  by  comy)ressed  air  supplied  by  an 
air  compressoi-  integral  with  the  frame.  The  pur- 
pose in  all  of  these  types  of  hannners  is  to  give  a 
cpiick,  shar])  blow.  They  are  started  and  stopped  l)y 
a  foot  treadle:  by  varying  the  pressure  on  the  treadle 


i 


93 


7 


I  I' 


94 


THE  MECHANICAL  EQUIPMENT 


t*   II 


any  desired  speed  or  force  of  blow  within  the  capacity 
of  the  machine  may  be  obtained.  They  are  used  with 
and  without  dies  for  drawing  out  handles  and  for  sur- 
facing round  work.  Hammering  is  continued  until 
the  work  is  cold.  The  work  is  rotated  meantime  and 
a  heavy  stream  of  water  is  played  upon  it,  which 
cracks  off  the  scale  and  turns  out  a  smooth  forging 
very  close  to  size  and  requiring  little  or  no  machining. 

Headers  and  Upsetters. — For  upsetting  heads  on  the 
ends  of  long  thin  stock,  heading  and  upsetting  ma- 
chines are  used.  The  dies  for  the  purpose  are  usually 
in  three  parts,  one  on  the  movable  head  of  the  ma- 
chine (see  A,  Figure  19),  and  the  other  two,  B  and 
B',  carried  by  the  main  frame.  These  two  dies,  B,  B', 
in  the  main  frame  separate  to  allow  the  introduction 
of  the  heated  bar.  They  are  then  closed  together, 
and  the  third  portion  of  the  die.  A,  on  the  movable 
head,  advances  and  drives  the  hot  metal  into  the  im- 
pression in  the  other  two.  This  type  of  machine  is 
used  for  forging  bolt  heads,  automobile  valves,  and  so 
forth. 

Hydraulic  Press. — The  hydraulic  press.  Figure  20, 
consists  essentially  of  a  heavy  frame,  an  anvil,  and  a 
moving  head  which  may  or  may  not  be  provided  with 
dies.  The  head  is  operated  by  a  hydraulic  cylinder 
which  creates  the  pressure  used  in  the  forging.  The 
supply  of  water  for  the  cylinder  is  controlled  by  a 
valve  and  is  furnished  by  a  high-pressure  water 
pump.  This  type  of  machine  works,  not  by  blows, 
but  by  dead  pressure.  It  is  used  for  all  sizes,  but 
more  especially  for  large  work.  The  effect  of  a  ham- 
mer blow  is  greater  along  the  surface  immediately 


H 

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r.      s 

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t-< 

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fa 

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^^H 

be 

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ETT 
fact 

^^^H 

cp  s 

^^^H 

&?  c 

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fa 

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I  *    I 

'♦    '1 


h.  if  .; 


:i 


9 


114 


THE  MECHANICAL  EQUIPMENT 


any  dt'sirod  spoed  or  force  of  l)l()\v  within  tlic  capaoity 
of  \\\v  niMchine  iiiav  he  ohtaiiied.  Thev  are  used  with 
and  without  dies  foi'  drawini;'  out  handh's  and  for  sur- 
facing' round  work,  llannneriiii;-  is  coutinuiHl  until 
the  work  is  cold.  Tlie  work  is  rotated  meantime  and 
a  heavy  strcuim  of  water  is  phiyed  upon  it,  which 
cracks  off  the  scah'  and  turns  out  a  siuooth  for.n'ini;- 
very  ch)se  to  size  and  rvquirini;-  litth'  or  no  maciiining'. 

Headers  and  Upsetters. — For  uj)settini;  iieads  on  the 
ends  of  h)nu'  thin  stock,  headini;  and  ui)setting  ma- 
chines are  used.  The  dies  for  tiie  puipose  are  usually 
ill  three  parts,  one  on  the  movable  head  of  the  ma- 
cliine  (see  A,  Fi,i;ure  19),  and  the  other  two,  1>  antl 
IV,  carried  hy  the  main  frame.  These  two  dies,  I>,  IV, 
in  the  main  frame  se])arate  to  allow  the  intioduction 
of  the  heated  bar.  They  are  then  closed  together, 
and  the  third  portion  of  the  di(\  A,  on  tin*  movable 
head,  advances  and  drives  the  hot  metal  into  the  im- 
pression in  the  other  two.  This  ty])e  of  machine  is 
used  for  forging  holt  heads,  automobile  valves,  and  so 
forth. 

Hydraulic  Press. — The  hydraulic  press.  Figure  20, 
consists  essentially  of  a  heavy  frame,  an  anvil,  and  .i 
moving-  head  which  mav  or  mav  not  l)e  ])r()vided  with 
dies.  The  head  is  operated  by  a  hydraulic  cylinder 
which  cnnites  the  pressure  used  in  the  forging.  Th*' 
sup])ly  of  water  for  the  cylinder  is  controlled  by  a 
valve  and  is  furnished  by  a  high-pressure  watrr 
[)ump.  This  type  of  machine  works,  not  by  blow-, 
but  by  dead  |)ressur(\  It  is  used  for  all  sizes,  but 
more  esf)ecially  for  large  work.  The  effect  of  a  liai  i- 
mer   blow    is   greater   along   the   surface   immediate  y 


s 


> 

si 


o 

u 

o 

A 

o 


r       P    0)    4> 

o 
o 

s, 


o 


o 


FORGING  METHODS  97 

SdrkuHe  L*  %f '*'^'    '•^^orseless    action    of    the 

with  die  forgrn/fLmhrf/^rr^^'  ^"  connection 
be  used      AH^     l^,       ^^""^  *^^*  ^^^t  i^n  dies  may 

hLTer;   fhe'T     *^'^  '"'^  '^'^^  ^^^  "^^  in  drop 
verTuTc'ertain  .f  ""*  ^'"^^^'  ^"^  their  life  I 

tuany  gSwav     r''  "''''  crystallizes  and  even- 
nari  V  usid  •  T/"    ^""^^'^"^""y'  steel  dies  are  ordi- 

be  dLSill^r  ^tLr  y  :  StTri^ns'tr^^ 

tsioTi:  Jhld^^^^^"^^^^^^^^^^^  ^^ 
of  die  forJnf  fl  ,f '*  ^""^  *^"«  P^™its  the  use 

Justified  S'sttl  dTes  t  •""'''!"  *'^"  "^'^'^  ''^ 
already  pointed^, t:  acZ^ofleTySr.  ^^ 

a  n^  ::i;-f  pSi  {~^^^ 

high-pressure  iX  ^d      ?  LLl  ^ t  "/"^ 
capacity  of  14,000  ton"™  '^"'"P""' ''«'  « 

»<  r„i„i  "■;,  r:i°"  o  tT;"a;  '.r''  "*"" 


[E3lit 


SKJ 


o 


o 

JD 

53 

y. 

O 

L< 

0* 

x: 

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■^ 

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w 

w 

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^ 

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^^  tr  — 

Oi 

ti-7  =; 

M«    */ 

c 

y. 

1.      ^    •'♦H 

^^ 

o 

"mf       —     ^"^ 

ca 

Ci  .1^ 

o 

-*-.-; 

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— »         ^M> 

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• 

1—1 

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f"^      — "    ,-r-l 

6 

a, 


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J 

H-^ 

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■;: 

C^l 

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*-< 

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iinrlor  (ho  ] 


F01?0I\0  MKTJfODS 


97 


w 


'-^^S*    while    the    ^\ 


•••''»y;MMs  ;n.<i  tlHMnetal  tends  to  ivork  side. 


Iiydnuilic  press  allows   11 


<>^v^    remorseless    action    of    the 


P'ii'<    of    the    t 


rounder   woi*k.     It    j 


^>^".i^ni.i;     iind,     thorel 


Willi  die  foroino.  jVoni  ll 
•<^  ii'^od.     Allhoiioh   (I 


O'O 


1 1  an 


liners. 


th 


<*n-  nse  is  not 


o  pressuri^  to   reaeli   every 
'ons    it    ])roduces 
in   connection 
may- 
op 


''«'^   an    advanta 


•<'  Hict  tlial  cast 


n-on  dies 


very    unecM'lain. 


Iiiall 
nai'il 


as   11 


niay  also  he  us(m1  in  di 
f^iioral   and  their  life  is 


^Jves  way.     C^onsc 
y  \\^('^\\  III 


ic   metal    crvstall 


izes 


quently,  steel  d 


and 


ev(»n- 


ics  are  ordi- 


^'•^y  are  expensive  to  make,  hnt  wher 


;;uniy  piece.  ar<.  |o  he  made,  XX,,  ehar^e  f^ 


he  distrihuled 


II 


lere  a 


^•<'  I  ml  a  few  j) 


ov(T  I  hem  and  is  not 


r  dies 


may 


leces. 


'Senons.     Where 


IHvssion  l()W(M-s  the  die  cost  and  W 


the  ahility  to  cast  W 


le  im- 


<>r  di(^  foi 


o 


'"^'  for  small 


us  permits  the  use 


.lustilied  with  sttH'I  dies  I 
>''-^;a<ly  pointed  ont,  the  .ictioTorihe 


quantities  tlian  would  be 
impressions.     As 


iavin.2-  cut 


'-^  very  quiet  and  it 
^•cry  large  work,  suci 


hydraulic  press 


^Iiaftf 


'hid 


>  and  so  forth.     The  plant 


IS  now  used  almost  entirelv  for 
I  as  armor  plate  foi 


liiiii 


f's   not   onlv   tl 


i(> 


i-pressure    pumps    and 


Pivss   \U(M,   hnt   tl 


i-oquired— whic] 


eavy 
1  in- 


P<'"sive,  and  this  form; 


connections 


10   uiH'essarv 
-IS    verv    ex- 


'^'le  hydraul 


serious  limitation  to  it 


H'  \M'^^^,  however,  is  tind 


)een 


avor,  and   j)lants   have   1 
i^e^one  us(hI  in  the  Bethlehem'steel 
apacty  of  14,000  ton 
Rolling".— A 


s  use. 

ing  increasing 

installed   of  enormous 


Con 


U^any  has  a 


-AS 


II 


o 


ol 


roll 
roll 


'*'  ^''''"^^  i^lpli(^s  Ihis  |)roee 


'".^'  the  metal  out    hetw 
n   is  used    for  lo 


ess  consists 


i'V^. 


^^'ork  usually  of  unifoi 


<'»'n  the  eurved  surf 
".i^-  and  thin. 


ni  cro 


:ices 


or  narrow 


ss 


section,  such  as  flat 


98 


THE  MECHANICAL  EQUIPMENT 


II' 


plates,  steel  rails,  I-beams,  channels,  and  angles,  as 
well  as  for  merchant  shapes,  which  are  bars  in  stand- 
ard sizes  of  round,  square,  and  rectangular  section. 
The  rolling  process  forms  the  backbone  of  the  steel 
mill  industry  and  is  also  important  in  the  brass  in- 
dustry. Eolling  mills,  vary  in  size  from  small  ones 
which  are  operated  by  hand  or  gear-driven  from 
shafting,  to  the  largest  sizes  which,  with  their  auxili- 
ary equipment,  driving  engines,  etc.,  fill  the  whole  of 
a  large  building  and  represent  an  enormous  invest- 
ment. 

Rolls  producing  bars  and  shapes  fall  under  two 
classes,  which  are  known  as  the  two-high  and  three- 
high  rolls.  In  the  two-high  roll  it  is  necessary  to 
reverse  the  direction  of  the  roll  for  the  return  pass  or 
to  send  the  material  back  for  the  next  rolling.  The 
material  is  usually  put  through  the  roll  a  number  of 
times;  each  pass  through  a  smaller  groove  in  the  rolls 
reduces  the  section  of  the  bar  and  increases  its  length. 
The  distance  between  the  centers  of  the  rollers  is  ad- 
justable, so  that  the  size  of  the  section  to  be  rolled 
may  be  varied.  The  three-high  roll  is  similar  to  the 
two-high,  except  for  the  addition  of  a  third  roll.  All 
three  rolls  revolve  continuously,  so  that  adjacent  sur- 
faces of  the  first  and  second  rolls  are  moving  in  one 
direction  while  those  of  the  second  and  third  are 
moving  in  the  reverse  direction.  The  material,  there- 
fore, which  has  been  passed  between  the  lower  and 
middle  rolls  may  be  returned  between  the  middle  and 
upper  roll  with  a  consequent  saving  of  time  in 
handling. 

The  rolling  process  is  used  not  only  for  continuous 


FORGING  METHODS  99 

work  of  uniform  section,  but  also  for  forging  separate 
pieces  which  are  relatively  long  and  narfow^and  va^^^^^ 
m  cross  section  such  as  axles,  sword  blades,  knife 
blades  wrench  handles,  etc.  Figure  21  shows  k  forg- 
ing rolof  this  type.  Th.  dies,  with  the  impressions 
cut  m  their  surfaces,  do  not  extend  entirely  around 
he  rolls;  hence,  when  the  free  sections  of  the  upper 
and  lower  dies  are  opposite  each  other,  there  is  an 
opening  between  the  rolls  into  which  the  stock  is  in- 

w^  ^  Z  "^  '''  ^^'  ^^"^^-    The  rolling  motion  is 

toward  the  operator,  so  that  when  he  reaches  forward 
and  inserts  material  between  the  rolls,  it  is  caught  by 
th    dies  and  is  rolled  back  toward  him.    In  this  man^ 

hands  in  fl!'  """  ?"^''  "^  '^'  ^P^^^*^^  '^''^^S  his 
hands  m  the  machine.    As  in  other  rolls,  there  may  be 

a  series  of  impressions,  each  approaching  the  desired 

t)e  needed  to  forge  an  article  broadside 
Drawing.-The   drawing  process   is  used  for  the 

bars   until  the  section  is  small  enough  to  be  handled 
in  sectior'7-^^^^^^       ?"'  '"^  '^  ''''  ^^'  i«  -^d^^ed 
the  desired  size  and  shape  in  a  hardened  die     The 
end  IS  seized  and  the  rod  drawn  through  the*  open 
ing  reducing  its  cross  section  to  the  size  of  Jhe  h'oTe" 

eac   T^^r"^^         "^'^  *^^^^^^  --^--e  dies,' 
each  of  which  reduces  the  section  a  certain  amount 

tney  will  harden  and  become  brittle  after  a  certain 
percentage  of  reduction.    Ductility  may  be  reared 


100 


THE  MECHANICAL  EQUIPMENT 


by  annealing,  that  is,  by  heating  and  subsequent 
cooling,  and  the  process  may  then  be  repeated  with 
alternate  drawing  and  annealing  down  to  the  manu- 
facture of  the  finest  wire. 

Extrusion  Process.— This  is  the  reverse  of  drawing 
and  might  be  compared  to  a  potato  ricer  on  a  large 
scale.  The  metal  is  passed  through  dies  of  the  re- 
quired size  and  shape,  but  it  is  forced  or  extruded 
through  instead  of  being  pulled  through  as  in  the 
drawing  process.  This  method  is  used  in  the  manu- 
facture of  brass  bars  and  shapes.  It  requires 
enormous  power  which  is  usually  supplied  by  a  large 
hydraulic  press.  An  ingot  is  placed  in  an  enclosed 
space  and  a  ram  coming  forward  drives  the  hot  metal 
through  the  holes  in  the  die  at  the  other  end.  By 
this  process  an  ingot  six  or  eight  inches  in  diameter 
and  several  feet  long  may  be  reduced  to  a  number  of 
bars  one-half  inch  or  so  in  diameter,  which  may  be 
taken  to  draw  benches  and  finished  by  the  more  ac- 
curate process  of  drawing.  The  extrusion  process 
can  be  used  for  the  production  of  fairly  intricate 
shapes,  such  as  stair  railings,  which  cannot  be  made 
by  the  drawing  process. 

Pipe  Bending. — Another  form  of  forging  which  may 
be  done  either  hot  and  cold  is  known  as  the  pipe 
bending  process.  Any  one  who  has  bent  a  paper  roll 
knows  that  a  tube  will  collapse  at  the  point  of  bend- 
ing unless  the  sides  are  prevented  from  coming 
together.  A  metal  pipe  which  is  to  be  bent  is  filled 
with  sand  or  other  resistent  material  which  will  stand 
heat.  Then,  since  the  pipe  cannot  collapse,  the  fibres 
on  the  outside  of  the  bend  are  stretched,  those  on  the 


FORGING  METHODS  loi 

used  L^Idi^g  llLTZ  Tofr  '^^^  "^^^  '' 

of  the  weld     V^iV    ^  ^      ^^  ^"^  ^^^^  "P  t^^  joint 
bent  ;^^1,e^;irn  Ti^t^'^^^ 

Z  fend  "  °f '"  ^"^^^^"^  "-  decreas  d  a„7wLr 
used  to  give  the  desired  radius  of  curvature-  fnr 

a  core    tor  large  pipmg,  such  as  steam  mains    efr- 

endroft?'"^  "*  ^°  '  '''''  floor-plarand  the 
tackle!  '''^'  '"  ^""^'^  ^^°-d  *'y  -«dla.s  and 


1  I 


E'Wii 


!  '»l 


CHAPTER  VIII 
DROP  FORGING 

Utility.— Drop  forging  is  an  application  of  manu- 
facturing methods  to  the  forging  process,  developed 
by  the  American  gun  manufacturers  about  the  middle 
of  the  last  century.  It  consists  of  hammering  the 
material  between  two  dies,  one  of  which  is  carried  on 
the  anvil  and  one  on  the  face  of  the  hammer,  and 
forcing  the  material  into  accurately  registered  im- 
pressions cut  in  the  faces  of  the  dies.  Drop  forgings 
are  produced  in  an  almost  infinite  variety  of  shapes 
and  can  be  made  close  to  size  and  in  great  quantities. 

Great  advancement  has  been  made  in  the  art  and 
its  scope  and  usefulness  are  being  steadily  widened. 
It  is  now  an  important  element  in  the  manufacture  of 
many  types  of  interchangeable  products,  such  as  fire 
arms,  sewing  machines,  automobiles,  machine  tools, 
and  so  on.  The  field  of  the  drop  forging  process  is 
confined  chiefly  to  smaller  forgings,  not  so  much  from 
any  mechanical  limitation  of  the  process  itself  as 
from  the  fact  that  few  large  forgings  are  produced  in 
quantities  sufficient  to  warrant  the  expense  of  the 
necessary  dies.  Automobile  steering  parts,  crank 
shafts  and  axles  represent  about  the  limit  of  drop 
forging  at  the  present  time,  but  there  is  no  reason 
why  the  process  may  not  be  extended  to  larger  work 
if  occasion  requires. 

102 


DROP  FORGING 


103 


Two  auxiliary  processes  accompany  or  follow  the 
work  of  forging.  During  the  forging  a  small  amount 
of  material,  called  ** flash,''  is  forced  out  of  the  im- 
pression into  a  thin  space  provided  between  the  face 
of  the  dies.  This  is  trimmed  off  either  during  or 
after  the  forging  process.  During  the  forging,  also, 
a  thin  scale  of  iron  oxide*  is  formed  which  is  removed 
later  by  pickling  or  in  the  sand  blast. 

The  drop  forging  process  is  subject  to  some  limita- 
tions.     Forging  dies  correspond  roughly  to  the  cope 
and  drag  of  the  sand  mold  used  in  the  foundry,  and 
impressions  in  the  dies  to  the  impressions  left  in  the 
molds  when  the  pattern  has  been  removed.    In  foun- 
dry  work   the  sand  mold  is   temporary  and  is  de- 
stroyed after  the  casting  has  been  poured,  therefore, 
the  casting  may  have  any  shape.    In  drop  forging 
the  dies  are  practically  permanent;  consequently  the 
forgmg  must  have  no  enlargements  or  bosses  which 
would  prevent  its  being  lifted  freely  out  of  the  im- 
pressions  in  the  die.    Furthermore  no  cores  are  pos- 
sible,  as  in  the  case  of  foundry  work,  on  account  of 
the  heavy  hammering,  of  the  obstruction  they  would 
offer  to  the  distribution  of  the  metal,  and  of  the  in- 
ability to  get  them  out  of  the  finished  forging. 

Drop  Hammer.— The  drop  hammer  consists  essen- 
tially of  a  heavy  steel  ram  sliding  between  two  verti- 
cal guides  mounted  on  an  anvil  or  block  which  forms 
a  base.  The  upper  die  is  keyed  to  the  hammer  head 
and  the  lower  die,  in  accurate  register  with  the  upper, 
js  keyed  to  the  base.  In  the  early  form  of  drop 
hammers,  used  in  the  Colt  Armory  about  1860,  the 
l^oads  were  lifted  by  a  vertical  rotating  screw  to  a 


'1,.;^ 


if 


104 


THE  MECHANICAL  EQUIPMENT 


definite  height  which  was  determined  by  an  adjust- 
able trip.  This  method  was  slow  and  has  long  since 
been  superseded.  For  light  work,  such  as  jewellers' 
hammers,  the  head  is  lifted  by  a  strap  which  runs  up 
over  a  pulley  and  down  to  the  floor  where  it  is 
operated  by  foot  power.  For  slightly  larger  hammers 
the  belt  may  be  operated  from  above  by  a  pulley  with 
various  forms  of  release  mechanism  to  allow  the 
hammer  to  fall.  While  a  few  belt  and  rope  drops  re- 
main, the  board  drop  has,  in  the  East,  practically 
superseded  all  others  for  medium-sized  work  and  the 
steam  drop  for  large  work.  In  the  Middle  West,  the 
steam  drop  is  used  for  light  and  medium  work  also. 
In  the  board  drop.  Figure  22,  one  or  more  boards 
are  keyed  into  the  top  of  the  hammer  head,  and  two 
rollers  at  the  top  of  the  hammer  are  pressed  together 
and  roll  the  board  upward.  When  the  head  has 
reached  the  height  desired,  a  trip  on  the  side  of  the 
hammer  head  operates  a  latch  rod  which,  in  turn, 
spreads  the  rollers  apart  and  allows  the  hammer  and 
board  to  fall  freely  on  to  the  work  below.  As  the 
hammer  reaches  the  bottom  of  its  stroke  the  latch  rod 
throws  the  rolls  together  again,  and  they  roll  the 
board  up  to  the  top  of  the  stroke.  The  operation  is 
controlled  by  a  foot  lever.  If  a  single  blow  is  desired, 
the  treadle  is  depressed  and  released  at  once;  the 
hammer  will  then  fall,  rise  to  its  top  position  and 
stop.  If  a  succession  of  blows  is  desired,  the  treadle 
is  held  down  and  the  hammer  will  continue  to  operate 
automatically  until  the  treadle  is  released.  Clear, 
straight-grained  maple,  free  from  all  knots,  is  the 
only  material  which  will  stand  up  under  the  severe 


t  • 


FIG.    22.      MEDIUM-SIZED   BOARD   DROP    HAMMER 

Cliamoersburg  Engineering  Co. 

105 


104 


THE  MECHANICAL  EQlIPMExNT 


(h'iiiiito  ]HM<;lit  which  was  di'tiM'iniiH'd  by  an  ad,iust- 
abh^  trip.  This  iiietliod  was  slow  and  has  h)n^-  since 
been  suporseded.  For  light  work,  such  as  jewellers' 
haniniers,  the  head  is  lifted  l)y  a  stra])  which  runs  up 
over  a  pull(»y  and  down  to  the  floor  where  it  is 
operated  l)y  foot  j)owcr.  Foi-  sli<;htly  lari^er  hammers 
the  belt  may  be  ()p(M-at<Ml  from  above  by  a  ])ulley  with 
various  forms  of  release  mechanism  to  allow  the 
hauunei-  to  fall.  While  a  f(^w  belt  and  rope  drops  re- 
main, the  board  drop  has,  in  the  Fast,  practically 
superseded  all  others  for  medium-sized  work  and  the 
steam  drop  for  lari»e  woi'k.  In  the  Middle  West,  the 
steam  drop  is  used  for  li^ht  and  medium  work  also. 
In  the  board  drop.  Figure  22,  one  or  more  boards 
are  keyed  into  the  top  of  the  hanuner  head,  and  two 
rollers  at  the  top  of  the  hammer  are  pressed  together 
and  roll  the  ])oard  upward.  AVhcn  the  head  has 
reached  the  heiglit  desired,  a  trip  on  the  side  of  the 
hanmier  head  operates  a  latch  rod  which,  in  turn, 
spreads  the  rollers  apart  and  allows  the  hammer  and 
})oard  to  fall  freely  on  to  the  work  below.  As  the 
hammer  reaches  the  bottom  of  its  stroke  the  latch  rod 
throws  the  rolls  together  again,  and  they  roll  the 
board  up  to  the  top  of  the  stroke.  The  operation  is 
controlled  bv  a  foot  lever.  If  a  single  blow^  is  desired, 
the  treadle  is  depressed  and  released  at  once;  the 
liannufM*  will  then  fall,  rise  to  its  top  position  and 
stop.  If  a  succession  of  blows  is  desired,  the  treadle 
is  held  down  and  the  hammer  will  continue  to  operate* 
automatically  until  the  treadle  is  released.  Clear, 
straight-gi-ained  maple,  free  from  all  knots,  is  the 
only  material  which  will  stand  up  under  the  severe 


PIG.  22.    iviEnir:ir-sizED  board  drop  hammer 

Chain iiershiir;;  IOnsineeriii«,'  Co. 
105 


L 


106 


THE  MECHANICAL  EQUIPMENT 


crushing  pressure  of  the  rolls.  It  is  expensive  and 
difficult  to  obtain,  and  many  attempts  have  been  made 
to  substitute  paper,  fibre,  and  other  materials,  but 
nothing  has  as  yet  proven  satisfactory.  One  of  the 
rolls  in  the  head  is  carried  in  fixed  bearings  and  the 
other  roll  is  mounted  on  an  eccentric  bearing  oper- 
ated by  a  latch  rod.  The  raising  or  lowering  of  the 
latch  rod  rotates  the  eccentric  and  presses  the 
movable  roller  in  and  out  against  the  board.  The 
rollers  are  driven  by  pulleys  and  rotate  continuously. 

The  weight  of  the  base  of  a  drop  hammer  should 
be  from  12  to  20  times  that  of  the  head,  as  a  heavy 
base  will  increase  the  size  of  the  forging  work  which 
inay  be  done  for  a  given  weight  and  fall  of  hammer 
head.  Board  drops,  as  in  the  case  of  steam  ham- 
mers, are  rated  by  the  weight  of  the  head,  which  runs 
from  200  up  to  about  3,000  pounds.  The  board  and 
friction  rollers  are  not  practicable  for  weights  beyond 
this,  and  the  larger  sizes  of  drop  hammers,  which 
range  from  3,000  as  high  as  12,000  pounds,  are 
operated  by  steam.  The  steam  drop  hammer  is  es- 
sentially the  same  as  the  board  drop  except  for  the 
lifting  mechanism.  It  corresponds  to  the  first  type  of 
steamer  hammer  mentioned  on  page  88,  except  for 
the  general  design  of  the  frame  which  conforms  to 
that  of  the  board  hammer. 

Trimming  Press. — ^It  is  impractical  to  guage 
exactly  the  amount  of  metal  necessary  to  fill  the  im- 
pression. To  make  sure  that  it  is  filled,  an  excess  of 
stock  is  always  provided  which  is  allowed  to  go  off 
sidewise  into  a  space  provided  between  the  surface 
of  the  dies.    The  fin,  or  flash,  which  results  must  be 


DROP  FORGING  107 

the  whole  run  has  been  made,  but  this  can  only  be 
done  on  small  work,  as  the  flash  is  thin  and  chills 
quickly  and  retards  forging.  For  large  work,  there- 
fore   to  allow  the  hammer  to  expend  its  energy  on 

I'n  T^V'l''''^/'^  ^^'  ^^^^'  ^  *^™^i^^  press  is  in- 
stalled at  the  side  of  the  hammer  and  the  forger  will 

step  over  to  the  press  and  trim  the  forging  once  or 
twice  during  the  progress  of  the  work. 

Dies—The  dies  for  drop  hammers  are  rectangular 
bbcks  which,  for  general  all-around  work,  are  made 
of  60-point  open-hearth  steel.  By  -60-point  steel-  is 
meant  one  having  six-tenths  of  one  per  cent  of  car- 

.  i  on  ^""^^  ''''"''^^^  ^^  *^^^  steel  forgings  are 
wanted  80  to  90-point  tool  steel  is  better;  and  for  the 
severest  use  3%  per  cent  nickel  steel  may  be  Led 

here  are  not  many  pieces.    It  has  been  considered 

treacherous  material  for  dies  and  is  only  used-  because 

the  impression  could  be  cast  in  the  face  and  little 

finishing  work  is  required. 

Recent  experiments  have  shown  cast  iron  dies  in  a 

mSriA^^^^  ^^  ^^^^^^^'  ''^  -ore  is 

wetht  of  ft  ?^P'^^T   P"''"'^   ''  ^^*^«^^«d   the 
weight  of  the  iron  and  consequent  crumbling,  which 

ordinary  sand  could  not  do.    The  molding  flasks  are 
m  three  parts-the  Mrag,'  containing  the  core  and 

pattern,   and   the  'cope,'  the   wood  pattern   of  the 

llT.i:\tT''^    '"^^^'  ''  P^^™^  '^^  -^te«  iron 
through  the  top,  a  special  inlet  is  made  through  the 


■I     •<t^\ 


.'I/ 


108 


THE  MECHANICAL  EQUIPMENT 


sand  and  to  one  side  of  the  mold,  allowing  the  iron  to 
run  out  gently  over  the  core  instead  of  falling  onto  it. 
In  this  way  the  mold  is  filled  from  the  bottom  up, 
making  possible  the  easting  of  delicate  impressions 
without  fear  of  breaking  the  sharp  corners.  A  riser 
is  left  in  the  top  of  the  mold  providing  for  th-e 
shrinkage  of  the  cooling  iron  and  for  bringing  the 
*slag'  to  the  surface.  All  that  remains  to  be  done  to 
prepare  the  castings  for  the  hammer  is  to  clean  out 
the  impressions  with  a  brush  or  die  and  to  stamp 
them  with  their  designating  numbers."*  The  reports 
of  these  dies  show  a  saving  in  time  and  expense. 
**The  maximum  time  required  to  turn  out  cast-iron 
dies  ready  for  the  hammer  is  four  days;  the  average 
time  for  steel  dies  is  between  one  and  four  weeks. 
*  *  *  In  many  cases  the  life  of  the  dies  nearly 
equals  the  average  duration  of  steel  dies.  Even  if 
cast-iron  dies  did  not  produce  one-third  as  many 
forgings  as  steel  dies,  the  saving  in  cost  would  be 
sufficient  to  justify  their  use,  letting  alone  the  time 
saved." 

The  backs  of  dies,  where  they  are  secured  to  the 
base  and  to  the  hammer  head,  are  provided  with 
dovetailed  shanks  which  slide  into  corresponding 
grooves  and  are  then  tightened  with  a  taper  key 
driven  in  by  a  sledge.  In  selecting  the  size  of  the 
die  blocks  sufficient  metal  should  be  left  around  the 
impressions  to  make  sure  that  the  die  will  not  split. 
For  ordinary  work  1^2  inches  is  enough.  The  depth 
of  the  blocks  runs  from  about  the  same  as  the  width 
to  about  %  or  2-3  of  the  width;  for  wider  blocks  the 

♦American  Machinist,  October  12,  1916. 


DROP  FORGING 


109 


depth  increases.  A  die  14  inches  wide  would  be 
about  8  inches  deep.  The  length  varies  with  the 
forging  to  be  made. 

Die  Working.— The  first  operation  in  preparing  the 
blocks  IS  that  of  planing  the  edges  square  and  true, 
as  the  impressions  are  located  from  the  edges.  The 
blocks  are  then  turned  over  and  the  shanks  cut.  So 
far  as  possible  the  size  of  shanks  should  be  standard- 
ized to  insure  interchangeability  of  use  in  the  various 
hammers  available. 

Before  laying  out  the  impressions  one  or  more  tem- 
plates  are  made   of  sheet   steel,   the   principal   one 
giving  the  contour  of  the  forging  along  the  parting 
Ime  of  the  dies.    Other  templates  are  made  of  the 
cross   sections   at   various   points.     These   templates 
must  allow  for  the  shrinkage  of  the  forging,  for  any 
extra  stock  to  be  machined  off  later,  and  for  draft 
Draft  IS  a  taper  of  not  less  than  7  degrees  on  all 
straight  sides  of  the  forging  so  that  it  may  be  freely 
hfted  out  of  the  die.    Without  this  draft  the  forging 
IS  liable  to  stick  and  give  trouble.    If  possible  the 
draft  is  put  on  surfaces  which  are  to  be  machined,  as 
It  then  disappears  in  the  finished  piece.    More  draft 
should  be  allowed  for  an  internal  surface,  as  shown 
m    Figure    23,    than    for    an    outside    one,    as    the 
metal  in  shrinking  tends  to  seize  the  sides  of  a  pluR 
in  the  die  while  it  tends  to  free  itself  from  outside 
surfaces.    The  choice  of  the  best  parting  line  is  a 
matter  of  skill  and  experience.    Often  a  curved  sur- 
face IS  used  which  follows  an  available  line  in  the 
torgmg,  as  the  butt  plate  for  a  rifle  shown  in  Figure 
^%  and  the  receiver  shown  in  Figure  26.    This  is 


I 


no 


iliii 


TKB  MECHANICAL  EQUIPMENT 


•Spof^  Centering 


^P''"^    j^^       Flash 


w///////////y/////////. 


Outside  Praf/ 


Inside  Dfaff 


Oufside  ■■ 
Prarf 


flash 


FIG.    23.      LONGITUDINAL    SECTION    OF    A    DROP    FORGING    FOR    A 
CONNECTING  ROD   PRIOR  TO  THE  TRIMMING  OPERATION 

necessary  in  bent  pieces,  as  the  forging  must  in  all 
cases  lift  out  of  both  dies  freely. 

Having  determined  the  parting  line,  the  faces  of  the 
die  are  planed,  and  the  impressions  are  laid  out  with 
the  aid  of  the  templates.  The  impressions  in  the  two 
dies  are  right  and  left-handed,  so  that  they  will  match 
when  the  two  faces  are  brought  together.  The  num- 
ber of  impressions  required  depends  on  the  size  and 


FIG.   24.      DIE  BLOCKS  FOR  THE  BUTT   PLATES  OF   A   RIFLE 
SHOWING  INTERLOCKED  DIE 


DROP  FORGING  jij 

S'afd  ^^^^^  '"  ^^^-^^  th-e  is  a  rough- 

ing and  a  finishing  impression,  and  an  -ed^'-  or 
side  breakdown      Tho  loof  •  .  *^ugei      or 

function  irfl^./!  !i,         '  ^^""^  important,  as  its 

ine  sme  ot  the  blocks,  are  used  for  drawing  out  th^ 
stock.     In  Fia-nrA  ')'^  th<.  «„  *     •         "'"wing  out  tJie 

the  original  b^s  oef  Ld  Ihrslcfn^  T"^  "' 
after  the  fuller  has  drawn  itttTudlh?  X^'Z 
readvin  l\  ""t'  "  *'^"  substantially  i/plaee 

Alter  the  forging  impressions  have  been  or^^    fi. 
surface  of  the  die  is  mi^lArl  «ff  +       \   ^        *'  ^^^ 
1/32-inch  for  a  w'dth  ZTvi^y"  \^T^  '^  ^''""t 
it  may  be  deepened  t  ilf  \    '^  "'?'  ''^^°°**  ^^^^^^ 

"®"  the  forging  is  completed.    Where   th^./ 

tlefac    ';r;^  tT^  ™P--ions  may  be  eft  on 
race  and  are  used  progressively.    The  last  im- 


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FIG.  25.      STAGES  OF  A  DROP  FORGING 

112 


DROP  FORGING 


113 


FIG.  26.      DIE  BLOCKS  FOR  A  SHOT  GUN  RECEIVER, 
SHOWING  INTERLOCKED  DIES 

pression  is  used  only  to  give  the  final  blow  and  bring 
the  work  to  size.    Letters  may  be  cut  in  this  im- 
pression so  that  the  forging  bears  some  desired  mark- 
ing, such  as  the  maker's  name,  the  size,  or  part  num- 
ber.   By  the  time  the  forging  has  reached  this  last 
impression  it  has  assumed  almost  its  final  shape  and 
the  only  work  to  be  done  is  to  bring  out  sharply  the 
details,  such  as  the  lettering  referred  to.    By  this 
succession  of  impressions  the  last  one  retains  its  ac- 
curacy a  long  time.    The  side  impressions  used  for 
the  preliminary  work  are  called  the  "breaking  down" 
impressions,  and  the  upper  ones  "finishing"  impres- 
sions.   The   impressions   will,   of  course,   wear   out 
lias  appears  by  the  rounding  off  of  corners,  and  the 
gradual  widening  of  the  impression  and  loss  of  definite- 
ness.    ihe  dies  may  sometimes  be  re-faced  and  re-cut 


114 


THE  MECHANICAL  EQUIPMENT 


Often  they  fail  by  cracking  or  splitting,  which 
precludes  their  further  use.  After  dies  are  cut  they 
are  usually  hardened  on  the  face  and  shanks,  as  these 
are  the  two  portions  subject  to  wear.  Some  makers, 
however,  have  the  shanks  soft  and  claim  better  re- 
sults against  breakage.  It  is  desirable  that  the  main 
portion  should  be  as  tough  as  possible  and  conse- 
quently these  are  left  unhardened.  In  order  to  in- 
sure the  registering  of  the  two  impressions  they  are 
accurately  located  with  reference  to  the  planed  edg«s. 
When  the  dies  are  set  in  the  hammer  they  are  lined 
up  by  these  edges  and  it  is  then  known  that  the 
position  of  the  impressions  is  correct. 

Heating. — In  heating  steel  for  forgings,  the  tem- 
perature should  be  raised  slowly  to  about  600  degrees 
Fahrenheit,  and  after  that  it  can  be  raised  as  quickly 
as  desired  to  the  welding  temperature.  This  is  due 
to  the  fact  that  steel  is  not  ductile  below  about  600 
degrees  Fahrenheit,  and  is  not  fitted  to  resist  the 
strains  imposed  upon  it  by  the  differential  expansion 
of  an  unevenly  heated  metal. 

By  heating  suddenly,  the  outer  shell  becomes  red 
before  the  core  has  had  an  opportunity  to  absorb  any 
heat,  and  great  strains  are  thus  caused  by  the  ex- 
pansion of  the  outer  shell.  Due  to  these  changes 
when  heating  up  cold  steels  and  especially  the  high- 
grade  alloys,  many  poor  forgings  are  turned  out  by 
raising  the  temperature  of  the  metals  too  suddenly. 

The  Forging  Operation. — Drop  forgings  are  made 
from  forging  bar  stock  cut  into  convenient  lengths 
to  make  a  certain  number  of  forgings  and  heated 
usually  in  gas  or  oil  furnaces.    When  ready  for  forg 


DROP  FORGING  115 

ing  the  heated  end  of  the  bar  is  placed  under  the 
hammer,  drawn  out,  if  necessary,  on  the  fuller,  and 
bent  into  the  approximate  shape  on  the  edger.  It  is 
then  laid  over  on  the  face  of  the  die  on  the  forging 
mipression  and  the  forging  work  is  performed.  As 
the  metal  is  brought  to  size  the  flash  begins  to  appear 
and,  in  the  case  of  large  forgings,  is  trimmed  off  as 
the  work  progresses. 

The  number  of  blows  required  varies  with  the  size 
and  shape  of  the  work.  Small  and  simple  work  may 
be  forged  in  one  or  two  blows,  while  large  work  will 
require  many.  Thin  sections  require  a  larger  ham- 
mer  and  more  blows  than  a  thick  or  chunky  one,  as 
the  hot  metal  is  exposed  to  the  cold  surface  of  'the 
dies  and  chills  quickly.  When  the  forging  is  finished 
It  IS  cut  off  at  the  sprue  and  drops  out  on  the  floor, 
while  the  bar  is  returned  to  the  fire  for  reheating 

Pickling.— After  the  forgings  are  made  they  are 
pickled  by  dipping  in  dilute  sulphuric  or  hydrochloric 
acid  and  rinsed  off  in  hot  water.  This  operation  is 
similar  to  that  already  described  for  castings  in 
foundry  work. 

Cold  Trimming.-Small  forgings  are  always 
trimmed  cold,  as  it  is  much  faster  and  cheaper  than 
hot  trimming.  This  work  is  done  in  stamping  presses 
and  the  forgings  may  be  handled  by  hand.  Trim- 
ming dies  have  the  form  of  the  forging  around  its 
parting  line.  For  ordinary  work  thev  are  flat  with 
their  cutting  edges  in  one  plane.  The  trimming  dies 
tor  forgings  having  an  irregular  parting  line  must  be 
oent  to  conform  with  the  surface  of  the  forging  dies. 
If  the  piece  is  to  have  a  hole  in  it,  the  flash  which 


116 


THE  MECHANICAL  EQUIPMENT 


closes  this  hole  must  be  trimmed  separately  from  the 
flash  on  the  outside.  Forgings,  like  castings,  are  sub- 
ject to  shrinkage,  and  consequently  the  size  of  hot 
trimming  dies  must  be  larger  than  the  finished  work 
for  they  do  their  work  before  the  shrinking  has 
taken  place,  and  the  parting  template  used  to  lay  out 
the  forging  dies  may  be  used  to  lay  out  the  trim- 
ming die.  Cold  trimming  dies  are  the  size  of  the 
finished  forging.  The  steel  for  the  trimming  dies  is 
usually  60  to  70-point  carbon  tool  steel,  hardened  and 
tempered,  while  the  punch  may  be  low  carbon  steel 
as  it  has  merely  to  push  the  forging  through  the  die, 
the  lower  end  being  shaped  to  fit  over  the  forging 
like  a  saddle.  Trimming  dies  are  usually  sectional- 
ized  or  made  in  a  number  of  pieces  fitted  together 
and  mounted  on  a  plate.  This  is  to  permit  regrinding 
when  necessary.  Otherwise  the  size  when  once  lost 
could  not  be  restored. 

On  account  of  the  shrinkage  forgings  will 
inevitably  distort  somewhat  in  cooling.  If  they  are 
restruck  when  cold,  in  dies  accurately  cut  for  that 
purpose,  certain  dimensions  may  be  brought  to 
within  .001  or  .002-inch  of  specified  size.  Conse- 
quently this  work  is  sometimes  done  when  great  ac- 
curacy is  required,  or  to  straighten  forgings  bent 
during  the  trimming. 

General  Considerations.— The  range  in  size  of  drop 
forgings  is  from  small  pieces  the  size  of  a  thimble  to 
pieces  weighing  100  or  200  pounds.  The  process  is 
limited  in  its  application  by  the  cost  of  making  dies, 
and  these  are  justified  only  for  a  comparatively  large 
number  of  pieces.    Where  forgings  are  to  be  drilled 


DROP  FORGING  ny 

later  at  right  angles  to  the  parting  plane,  the  holes 
may  be  located  quite  accurately  in  the  drop  for^in^ 
by  what  IS  known  as  -spot  centering,-  whereby 
conical  depressions  are  formed  at  the  spot  where  the 
hole  IS  to  be  drilled,  acting  as  a  starting  point  for 
guiding  the  nose  of  the  drill.  Frequently  drop  for^- 
mgs  are  forged  in  one  plane  and  then  bent  in  a  sub- 
sequent operation.  A  conspicuous  example  of  this  is 
that    of   six-throw    cranks    for    automobile    engines. 

the  shaft  IS  then  twisted  in  a  subsequent  operation  so 
that  the  cranks  will  stand  at  the  required  angles. 
Frequently  when  the  forgings  are  small  and  simple  in 
shape  two  or  more  may  be  forged  at  once.     The  dies 


.'m 


Ill 


II 


CHAPTER  IX 
WELDING,  SOLDERING  AND  BRAZING 

General  Classes  of  Welding. — Welding,  as  a  branch 
of  blacksmithing,  is  a  very  old  process — a  general  out- 
line of  smith  welding  was  given  in  the  chapter  on 
Forging.  Of  recent  years  new  methods  and  ma- 
chines have  been  developed  which  have  enormously 
increased  the  importance  of  welding  and  extended 
its  use. 

Welding  is  the  uniting  of  metals  into  one  piece  or 
mass  by  hammering,  pressing,  or  casting  them 
together  while  in  a  heated  condition.  Soldering  is 
the  uniting  of  two  pieces  of  metal  with  a  third  metal 
applied  in  a  molten  state.  Brazing,  really  a  form  of 
soldering,  is  the  uniting  of  two  pieces  of  metal  by  a 
thin  film  of  soft  brass.  These  processes  run  into  each 
other  more  or  less.  Two  unlike  metals  such  as  iron 
and  platinum  may  be  welded,  while  two  pieces  of  steel 
may  be  united  by  placing  platinum  foil  between  them, 
pressing  them  together,  and  heating  them.  While 
this  is  strictly  welding,  yet  the  platinum  foil  acts  as  a 
solder. 

There  are  two  general  classes  of  welding:  First, 
pressure  welding — which  includes  both  hand  and 
steam-hammer  work  on  wrought  iron  and  steel — and 
electric  resistance  welding,  known  as  the  Thomson 

118 


WELDING,  SOLDERING,  BRAZING  119 

process;  and  second,  welding  by  casting,  which  in- 
cludes electric-arc,  gas-flame  and  thermit  welding. 

Welding  under  pressure  is  a  mechanical  process, 
not  a  chemical  one,  and  depends  upon  the  plasticity 
or  flow  of  the  metal  as  well  as  upon  the  wetting  or 
cohesion  of  the  two  surfaces  at  welding  heat.  The 
latter  can  occur  only  when  the  two  metallic  surfaces 
are  m  absolute  contact.  The  interposition  of  any 
foreign  substance,  such  as  a  film  of  oxide  which 
cannot  be  pressed  out  by  hammering  or  other  means, 
precludes  welding.    As  pointed  out  on  page  87   the 

::lZ/'  'ZV""  '^™  ^  «"^^  «lag  by  chemica 
combination  with  the  oxide  which  can  be  pressed  out 

and  allow  the  two  surfaces  to  come  into  actual  con- 

n.?"-  T'^  P^'^P"'"'  P'""^^"'"^  welding  must 
be  done  ma  few  second's  time,  and  the  previous 

notT/tr  ,  'r""^  ""^^^  "•'*  *^^^  ''^«-  Were  it 
and^h.r  .  "'  ^'''  «^y-l»ydrogen,  oxy-acetylene, 
and  thermit  processes,  commercial  welding  would  be 
confined  to  wrought  iron,  steel,  nickel!  and  the 
precious  metals. 

The  term  autogenous  welding,  as  applied  to  the 
eectnc  arc  and  gas-flame  methods  is  a  misnomer 
since  It  means  self-welding.    Fusion  welding  Tuld' 

vlrZlVTT  "°'^^^  ''''  ^^^'•^-^'y  hfgh  tern 
ftto  ?„  "    T  ^"""^  "If  ^  ^^'  "^«*^1  I««^"y.  causes 

as  w!fr'  ^'^fi^.^y  Hammering._What  is  known 
a^^^w   ding.heat  varies  with  different  compositions^ 

grade,  to  dazzling  white,  about  1,500  degrees.    As 


II 


120 


THE  MECHANICAL  EQUIPMENT 


already  pointed  out  (see  page  87)  the  material  mnst 
be  heated  cleanly  in  a  reducing  fire,  and  the  surfaces 
must  be  shaped  or  prepared  for  the  joint.  As  the 
strength  of  a  welded  joint  is  less  than  that  of  the 
stock  itself,  the  joint  is  usually  made  on  an  angle. 
Scarfing  the  joint  at  an  angle  strengthens  the  joint 
by  increasing  the  welding  surface,  and  makes  it 
easier  to  apply  the  heavy  pressures  necessary  to  bring 
the  surfaces  into  contact.  In  general,  large  welds  are 
unreliable,  as  it  is  difficult  to  insure  perfect  contact 
over  all  of  the  surface  to  be  welded,  and  for  this 
reason  steel  castings  are  superseding  built-up  forg- 
ings  for  large  pieces  such  as  ships'  frames,  rudder 
posts,  and  locomotive  side-frames. 

Copper  is  weldable  by  pressure;  it  is  not  often 
welded  in  this  way,  however,  since  soldering  or 
brazing  is  preferred.  To  weld  copper  the  metal  is 
heated  to  redness,  calcined  flux  containing  borax  and 
a  phosphate  salt  is  sprinkled  on  the  surface,  and  the 
pieces  are  joined  at  a  yellow  heat  and  hammered 
together,  as  in  iron-welding.  Copper  may  also  be 
welded  by  the  electric  process.  Aluminum  may  be 
pressure-welded,  but  it  is  not  easy  to  keep  the  ends 
free  from  oxidizing.  The  usual  method  of  welding 
is  by  the  oxy-acetylene  process,  described  later. 
Platinum,  gold,  and  silver  may  also  be  welded,  but 
need  not  be  considered  here. 

Many  manufactured  products  are  based  on  the 
process  of  welding.  The  oldest  of  these  are  welded 
pipe  and  chains.  Pipes  are  made  from  long,  thin 
strips  of  wrought  iron  or  steel  known  as  skelp.  The 
strips  are  curled  up  into   tubes  by   drawing  them 


WELDING,  SOLDERING,  BRAZING 


121 


LAP   WELD 


CORRECT  SCARFING 


I 


IMCORRECT  SCARFING 


BUTT   WELD 


ZJ 


CZHK 


JUMP  WELD 


CORRECT  SCARFING 


J      nZMMHI] 


INCORRECT  SCARFING 


CORRECT  SCARFING 


I 


:^ 


CLEFT  WELD.  USED  FOR 
STEEL 


Z2 


.SPLIT-WELD.  USED  FOR  THIN 
STOCK 


FIG.   27.      TYPES   OP  WELDS   WITH    CORRECT  AND 
INCORRECT  SCARFING 

through  circular  dies.    The  two  edges  are  brought 
ogether   and   welded,   in   the   case   of   butt   welds, 
by  being  drawn  through  the  annular  opening  between 
a  mandril  and  a  circular  die  slightly  smaller  in  size 
than  the  outside  of  the  pipe,  which  produces  the 
pressure  necessary  to  make  the  weld.    In  the  case  of 
lap  or  scarf  welds  a  roll  is  also  used  to  press  the  joint 
down  against  a  mandril  or  bar  inside  the  pipe.  Welded 
pipes  are  made  in  commercial  sizes  of  from  %-inch 
to  30-inch  internal  diameter.    Beyond  this  size  they 
a  e  generally  riveted.    High  carbon  steels  cannot  he 

r.r.  r  ^i^l'  ^'  ^^^^  '^"''^  '«  P°"rly  that  the  high 
f  hf tri  ^^l^l^^^^'^l  -  «ff-t  by  the  uncertainly 
ot  the  weld.    Chains  are  still  welded  largely  by  hand 
a  hou  h  3^  ,1  ^^        ^^^  ^^^  ^^^^  automati c'alirfn 

tTtCTr"  ■"'  *''  '''°™^°"  *yP«-    For  small 

]  eated^„             ^""  '"*  ^'""^  ^P''-^"^  ^"""d  bars, 

Wlr!  r     ^  ^^'  °^^'''  ^"^^  '^^««<^  «!•  scarfed  by  a 

hydraulic  press  with  a  die  of  suitable  shape  The 


^  1 


122 


THE  MECHANICAL  EQUIPMENT 


steel  for  chains  must  be  pure,  and  low  in  carbon. 
With  chains,  as  with  pipe,  the  strength  depends 
mainly  on  the  perfection  of  the  weld,  and  good  prac- 
tice limits  the  load  to  50  per  cent  of  the  working 
tensile  strength  of  the  material.  For  manufacturing 
purposes  electric  resistance  welding  and  the  various 
forms  of  fusion  welding  are  generally  more  efficient 
than  smith  welding. 

Electric  Resistance  Welding. — There  are  two  clearly 
defined  types  of  electric  welding — resistance  and  arc 
welding.  Resistance  welding  was  invented  by  Elihu 
Thomson  in  1877,  and  has  been  used  commercially 
since  1880.  In  this  process  a  large  volume  of  cur- 
rent at  low  voltage  is  forced  through  the  work  and 
across  the  joints  to  be  welded.  The  heat  developed 
at  the  point  of  contact,  which  is  the  point  of  highest 
electrical  resistance,  raises  the  temperature  of  the 
material  quickly  to  a  welding  heat.  At  the  same  time 
the  pieces  are  pressed  together  by  heavy  mechanical 
pressure,  which  forces  the  softening  surfaces  together 
so  that  complete  contact  is  effected.  The  metal  can 
be  raised  to  the  temperature  desired,  and  the  heat 
can  be  held  for  any  length  of  time  and  increased  or 
decreased  at  will. 

The  elements  of  the  apparatus  are  (1)  a  suppiy 
of  alternating  current  from  a  generator  or  power 
service  system;  (2)  a  step-down  transformer,  usually 
carried  in  the  body  of  the  machine,  to  lower  the 
voltage;  (3)  apparatus  for  regulating  the  current, 
sometimes  arranged  to  shut  off  the  current  automati- 
cally as  soon  as  welding  heat  is  reached;  (4)  clamps 
for  holding  the  metal  to  be  welded  and  transmitting 


WELDING,  SOLDERING,  BRAZING  123 

t?on«  wl*"  V\  "'""^  '''  ^^'•''^"^  tl^-  t^o  -c- 
Hre  bunffn  '■  ■?''^'"''  '^'"'>«dy'"g  these  elements 
tnfhrl  ^  ^  J  '  ^^"'*^  "*■  ^'^««  «"d  types  suited 
to  the  kind  and  section  of  metal  to  be  welded.  One 
or  them  is  shown  in  Figure  28. 
The  following  table  shows  the  power  and  time  re- 

anrstelP        ^^^^^  ""^  ^^"°"'  ^^^^  '^^^^""'  ^°  i™° 


Time  and  Poweb  Reqmbed  m  e,.ectr,c  Resistance  Welbino. 


Diameter 
Inches 


Area  in       I    Kilowatts. 
Square  Inches   Transformer 


V4. 

0.05 

% 

0.11 

V2 

0.20 

% 

0.31 

% 

0.44 

% 

0.60 

1 

0.79 

11/8 

0.99 

W4 

1.23 

IV2 

1.77 

1% 

2.41 

2 

3.14 

Seconds  To 
Make  Weld 


Cost  per  1000 
Welds  at  One 
Cent  per  Kilo- 
watt Hour 


The  Thomson  process  has  many  advantages.  The 
operation,  as  seen  from  the  table,  is  very  rapid.  Even 
as  many  as  twenty  welds  may  be  made  in  a  minute.  In 
chain.we  ding  ten  links  a  minute  can  be  welded,  of 

ndef     7  r'-    "^^^  ^^^""^  ^«  --'  local,  knd 
;»der^perfect  control.    There  is  little  danger  of  ex- 

♦  Machinery's  Reference  Book  No,  127.  p.  21. 


M\ 


i «? 


I     '• 


ill 


No 


Trofta/brmer 


f%ot-con!roi 


FIG.  28.      THOMSON  BUTT-WELDING  MACHINE 

124 


WELDING,  SOLDERING,  BRAZING  125 

cessive  heating,  as  there  is  with  the  arc  and  gas- 
flame  methods,  consequently  there  is  very  little  oxida- 
tion or  decarbonizing  of  the  material.  Practically  all 
the  heat  generated  goes  into  the  weld,  and  is  so  low 
that  the  whole  process  can  be  watched  with  the  naked 
eye.  Arc  and  gas-flame  welding  require  glasses  and 
a  hood  to  protect  the  operator's  eyes  from  the  blind- 
ing light,  and  this  hood  necessarily  is  a  hindrance 
to  the  worker. 

The  clamps  that  are  used  for  forcing  the  pieces 
together  may  be  machine-operated  and  accurately 
alhgned,  so  that  the  locating  of  the  parts  during  the 
weld  may  be  very  close.  There  is  a  high  power  effi. 
ciency  amounting  to  75  per  cent  and  over.  The 
power  IS  used  only  as  long  as  needed,  and  may  be 

moderate,  fimshed  or  nearly  finished  work  may  be 
^.•elded  with  little  or  no  damage.  Finally,  the  ap. 
paratus  can  be  operated  by  even  a  moderately  skilled 
workman  with  little  danger. 

The  method  has  been  applied  successfully  to  weld- 
ng  more  lands  of  metals  and  combinations  of  metals 

The  Thomson  process  is  better  adapted  to  "repeti- 
mes  T'~;°  ^7'°™'"^  '""^  same  operation  m'any 
<tpparatus  requires  a  more  or  less  elaborate  machine 

general  outside  work  as  gas-flame  welding     It  de 
2^a  large  amount  of  power  at  irregular  intervals, 

Modern  Shop  Practice,  Vol.  11,  p.  239. 


"  i 


. 


'Fhessurc  honcf/e. 


IBrec//rJir/7cA 


'Trarta/hr/ner 


f^ot-  cotifrot 
of-  bre<if<  srrifct 


v^#' 


FIG.    28.      THOMSON   1JUTT-WKL1)1X(J    MACHINE 

324 


WELDIXO,  SOLDERTXO,  BRAZING  125 

cessivo  liealinu-  as  tlioro  is  will,  tlie  arc  and  gas- 
ilamc  methods,  ('oi,sc(iiieiitly  there  is  verv  littlo  oxida- 
tion or  decarbonizing  of  tJie  inaterial.  Practically  all 
the  heat  g.^nerate<l  goes  into  the  wehl,  and  is  so' low 
that  the  whole  process  can  he  watched  with  the  naked 
eye.  Arc  and  gas-flanu^  welding-  require^  glasses  and 
a  hood  to  protect  th(^  operator^  eyes  from  the  l,lin<i- 
n.i;-  light,  and  this  hoo<l  necessarily  is  a  hindrance 
to  the  worker. 

Tlu.  .-lamps  (lu.f  .-u-o  usod  for  lo,-,.i„g.  i|h.  pieces 
to«vllu.r  nmy  l„.  ,na.-hin,.-operat.,l  an.l  accurately 
aII.Kn..<l,  so  that  the  locating,  of  the  parts  .luring  the 
^vehl  may  he  very  close.  Th.-re  is  a  high  power  effi- 
'■'wicy  amou.it.ng  to  n  per  .-..„t  ami  over.  The 
l">^^"'-  IS  u..,.,l  only  as  long  as  n.....le,|,  ami  mav  be 

■•'|"'l  off  n..stantly.     Sin.v  the  h.-ating  is  b.-afaml 

"'■''';■''  ^^"''  '""'■  "'•  >">  'l.-'.nag...  Finallv,  th.^  ap- 
i""-'l"s  .-an  l„.  „perat,.,l  by  evn  a  mo.leratelv  skilled 
workman  with  iitll..  danger. 

.    '•''"'  "'"tll'Ml  has  b,.,.n  applie,!  su....essfullv  to  w.-ld- 
;".«■  .M.nv  kin.ls  or  nu.lals  an.l  .•..n.bim.tion;  of  m.4ah 
'.■'-'  any  oth..-  proc.-.s.s,  as  „,ay  I,.,  s.-e,.  by  the  list  on 
(lie  tollowing  page.* 

'I'l';'  Th.,mson  pr.,....ss  is  b,.tter  a.lapt...!  to  "rep..ti- 
-  w..rk-t.,  p.Mfonning  th,.  san...  ..peration  nmnv 
'""••^-than  t.)  .loiMg  sp....ial  or  job  work  Th'.. 
•;i'l'=""<i-s  r...p,ir..s  a  mon-  or  l....s  elab.>rate  machine 
"""  -••'■;'l.v  portabl..,  an.l  is  (h,.r..for..  n<.t  .so  g.,od  W 
:-;al  outsi.le  w.,rk  as  gas-name  w..hling:  U  !;:: 
•'^mds_a  large  anu.unt  of  pow..r  at  irregular  intervals 

.M"(l,.|n  .SI,,,,,  [',-,„.(i(e.  Vol.  II,  ,,.    r^X  ' 


126 


THE  MECHANICAL  EQUIPMENT 


Wrought  Iron    Lead 
Cast  Iron  Tin 

Copper  Zinc 


METALS 

Antimony 

Cobalt 

Nickel 


Bismuth 

Aluminum 

Silver 


Platinum 
Gold   (pure) 
Manganese 


Brass 
Solder 
Stub  Steel 
Coin  Silver 
Gold  Alloy 
Cast  Steel 


KIckel  Steel 
Gun  Metal 
Fuse  Metal 
Type  Metal 
Chrome  Steel 
Mushet  Steel 


ALLOYS 

Crescent  Steel 
Bessemer  Steel 
German  Silver 
Silicon  Bronze 
Aluminum  Iron 
Aluminum  Brass 


COMBINATIONS 


Aluminum  Bronze 
Phosphor  Bronze 
Brass  Composition 
Various   Tool    Steels 
Various   Mild   Steels 


Copper  to  Brass 

Copper  to  German  Silver 

Copper  to  Gold 

Copper  to  Silver 

Tin  to  Zinc 

Tin  to  Brass 

Tin  to  Lead 

Brass  to  German  Silver 

Brass  to  Platinum 

Brass  to  Tin 

Brass  to  Mild  Steel 

Brass  to  Wrought  Iron 

Wrought  Iron  to  Cast  Steel 

Wrought  Iron  to  Mild  Steel 


Wrought  Iron  to  Tool  Steel 
Wrought  Iron  to  Mushet  Steel 
Wrought  Iron  to  Stub  Steel 
AVrought  Iron  to  Crescent  Steel 
AVrought  Iron  to  Cast  Brass 
Wrought  Iron  to  German  Silver 
Wrought  Iron  to  Nickel 
Mild  Steel  to  Tool  Steel 
Nickel  Steel  to  Machine  Steel 
Gold  to  German  Silver 
Gold  to  Silver 
Gold  to  Platinum 
Silver  to  Platinum 
Steel  to  Platinum 


and  for  tMs  reason  may  give  trouble  on  the  electrical- 
supply  lines  from  which  the  current  is  drawn.  These 
disadvantages,  however,  are  not  serious,  and  for 
manufacturing  work  this  method  of  welding  is  one  of 
the  most  useful  that  has  yet  been  developed.  It  has 
been  extensively  used  in  the  manufacture  of  bicycles, 
automobiles,  typewriters,  chains,  wire  fences,  rakes, 
and  railway  cars,  and  in  spot  welding  of  all  kinds. 
It  is  particularly  good  for  small  butt  welds.  The 
strength  efficiency  of  the  weld  is  very  high,  running 
from  75  to  95  per  cent,  and  even  over  100  per  cent 


WELDING,  SOLDERING,  BRAZING  127 

When  the  upset  resulting  from  the  weld  is  not  cut  off 
which    means,    of   course,    that   the   material    when 

welST  ?,?  "  l'^  °"^'"^'  ^^^^"^  -d  not  at  Z 
weld.    In  welding  chain,  from  10  to  30  per  cent  of 

the  joint.  This  loss  of  current  is  expensive,  and  con- 
titutes  one  of  the  reasons  why  hand  welding  Z 
holds  Its  place  in  the  trade.  The  loss  of  current  is 
less  for  large  rings.  Garden  rakes,  which  used  to  be 
eastings,  are  now  made  by  jump-welding  the  teeth  on 
to  the  crossbar.  Rail-welding  was  first  done  by  tMs 
process,  and  special  machines  have  been  deveUed 
for  this  particular  kind  of  work. 
La  Grange-Hoho  Piocess.-The  La   Grange-Hoho 

hea  nTV;r  '^"^-^  -^^  ^"  ''^'  -erely^'ele^S 

nof  as  ve^forr''  T^'""*'**  ^"  ^^'S'™'  «"d  has 
not  as  yet  found  much  use  in  this  country     The 

oiTe  Joir'l  '"  '^^^^"^^  ''  '"^^  -^-ti've  pole 
ot  the  circuit  and  immersed  in  an  electrolyte  bath 

such  as  potassium  carbonate  solution.    As  the  cur- 

ent  flows  from  the  positive  pole  through  the  soL 

taon  and  into  the  metal  pieces,  the  solution  begin^^^^^^ 

decompose  and  deposits  a  thin  film  of  hydrogen  aboS 

the  pieces,  protecting  them  as  thev  become  hot     As 

soon  as  the  welding  heat  is  reached,  the  piecl;  ate 

vithdrawn  from  the  solution  and  welded  between  tl  e 

hammer  and  the  anvil  i„  the  usual  manner     The  ad 

vantage  of  the  process  is  that  the  metals  are  cleansed 

rom  grease  and  dirt  by  the  bath,  and  are  pr  tec  ed 

fi  r   il  Tl  ^""^  ''''  ^^'^^'"^  »'y  the  hydrogen 
him.    The  heat,  however,  is  not  very  easily  controlled 
and  the  hot  metal  will  oxidize  in  the  air  Vhen  £ 


128 


THE  MECHANICAL  EQUIPMENT 


out  just  as  quickly  as  if  it  had  been  heated  in  a 
forge  fire. 

Electric-Arc  Welding.— The  three  best  known  sys- 
tems of  electric-arc  welding  are  the  Zerener,  the  Ber- 
nardos,  and  the  Slavianoff.  In  the  Zerener  process 
there  are  two  carbon  electrodes  mounted  in  a  frame 
that  holds  them  pointed  towards  each  other  and 
toward  the  work.  The  electric  arc  between  them  is 
deflected  by  a  magnet  and  used  in  the  same  way  as  a 
gas  flame.  Welding  material  is  furnished  in  the 
shape  of  a  melt, bar.  The  apparatus  is  bulky,  more 
or  less  complicated,  cannot  be  used  with  large 
amounts  of  current,  so  that  it  is  limited  to  use  in 
comparatively  light  work.  The  advantage  claimed  for 
this  system  is  that  the  arc  may  be  controlled  by  the 
magnet,  and  consequently  fine  work  can  be  done. 

The  Bernardos  system  allows  for  the  production  of 
an  electric  arc  between  a  carbon  negative  electrode 
and  the  material  to  be  welded.  Welding  metal  is 
furnished  by  a  melt  bar.  Direct  current  is  used. 
While  any  metal  which  does  not  volatilize  or  burn  too 
easily  may  be  welded  by  the  Bernardo  process,  it  is 
best  adapted  for  use  with  cast  iron,  copper  alloys, 
and  aluminum.  When  the  graphite  pencil  is  used,  a 
rotary  motion  is  given  to  it  which  causes  the  arc  to 
play  over  the  surface  of  the  job,  distributes  the  heat 
evenly,  and  prevents  burning.  This  motion  also 
drives  the  slag  or  impurities  off  to  one  side  and  away 
from  the  weld.  The  adaptation  of  the  Bernardos  arc 
to  cutting  is  of  recent  date.  When  used  for  cutting, 
the  arc  begins  at  the  top  and  moves  downward  across 
the  face  of  the  piece.    It  is  not  so  efficient  for  this 


WELDING,  SOLDERING,  BRAZING  129 

purpose,  however,  as  the  gas  flame,  which  makes  a 
cleaner  and  smaller  cut  and  clears  away  the  metal 
as  the  flame  advances. 

In  the  Slavianoff  process  the  welding  heat  is  pro- 
duced by  an  arc  between  the  melt  bar,  or  welding 
metal— which  forms  the  negative  electrode—and  the 
metal  to  be  welded.    Continuous  current  at  a  low 
voltage  IS  used.    After  the  arc  has  been  established 
by  touching  the  electrodes  together  and  separating 
then^  the  welding  pencil  begins  to  melt  and  furnishes 
the  fil  mg  material.     This  system  has  been  more  sue 
cessful  with  iron  and  steel  than  with  other  metals- 
Its  mam  application  has  been  in  sheet-metal  work,' 
the  metal  electrode  being  deposited  along  the  joint  to 
be  made.     The  current  required  for  this  Slavianoff 
process  is  much  less  than  that  for  the  Bernardos 
process,  but  its  action  is  much  slower  for  operations 
requiring   the   deposit   of   large   amounts    of   metal, 
l^robably,  however,  it  is  the  most  successful  of  the 
arc  welding  processes. 

All  three  of  the  arc  welding  methods  are  used  on 
large  and  varied  kinds  of  work,  such  as  jobbing  work, 
repairs,  and  so  on.     The  temperatures  in  the  arcs  are 
unknown,  probably  ranging  from  5,000  to  7,000  de- 
grees Fahrenheit,   which   is  far   above   the  melting 
point  of  any  metal.    A  skilful  operator  is  required 
and  great  care  must  be  used  to  avoid  over-oxidation 
and  burning  away  of  the  metal.    As  with  the  gas- 
flame  methods,  the  light  produced  is  blinding  to  the 
naked  eye  and  the  workmen  must  be  protected  by 
noods  or  glasses,  which  more  or  less  hamper  manipu- 


130 


THE  MECHANICAL  EQUIPMENT 


Gas-Flame  Welding.— These  forms  of  welding 
usually  take  their  name  from  the  gases  used,  as  oxy- 
acetylene,  oxy-hydrogen,  and  so  on.  The  oldest  of 
these  uses  an  oxy-acetylene  torch  which  is  practically 
a  blowpipe  that  burns  acetylene  gas  and  oxygen.  As 
first  applied,  these  gases  were  used  under  high  pres- 
sure; later,  low  pressure  systems  were  developed  and 
now  the  danger  that  attended  the  process  in  its 
earlier  years  has  been  largely  eliminated.  Figure  29 
shows  the  connections  of  a  typical  torch  with  a  section 
of  the  nozzle.  The  utility  of  the  torch  comes  from  the 
high  temperature  of  the  flame,  which  ranges  from 
6300  to  7000  degrees  Fahrenheit,  and  which  is  able 
to  bring  the  part  of  the  metal  acted  upon  to  a  molten 
condition  before  the  heat  can  be  radiated  or  con- 
ducted away.  This  makes  possible  welding  through 
local  recasting,  and  also  cutting  by  burning  a  section 
across  the  piece  to  be  parted.    In  welding  it  is  usu- 


JOXVOEN 


^CCTYLBNB 


&^^^m 


H 


FIG.    29.      OXY-ACETYLENE    WELDING    TORCH    AND    TIPS 

Davis-Bournanville  Co. 

H,  H,  Hose  connections,  with  needle  valves,  for  oxygen  and  acetylene. 
T,  Removable  welding  tip — five  tips  are  furnished  for  varying  pres- 
sures and  different  thicknesses  of  metal.  O,  Oxygen  inlet.  A,  Acety- 
lene inlet,  from  both  sides  at  right  angles  to  oxygen  inlet.  M,  mix- 
ing chamber  in  tip. 


WELDING,  SOLDERING,  BRAZING  131 

ally  necessary  except  in  the  case  of  very  thin  sheets, 
to  add  meta  to  the  joint.  This  is  melted  in  from  a 
weldmg  stick,  or  melt  bar,  of  the  same  material  as 
the  pieces  to  be  welded.    If  the  metals  joined  are 

mlTi":  "  t'^  ''  ""*^""'  ^^^^^"^  the' same  ele^ 
Ted  TV.  T  '°\'*  ^  ^'^''  temperature  should  be 
3;,       1    T^  '^""'"^  ^^  '^'•««  ^"«"gh  to  heat  the 

consumnfL  T''''  ^T ''^  «™^  ""^^  ^  "-^^-naWe 
consumption  of  gases.    Ordinarily  the  flame  is  manip- 

1  ated  by  hand,  but  recently  various  forms  of  apZ. 

directed  in  a  deS  ^a^.'^^Tl^isTes^Tar:^^^^^ 
ful  in  cutting  and  spot  welding  ^ 

pressurTt/fir'  f"  l'"'*.""''  ^''  «^  "^^^^^  ™der 
pressure  is  fed  into  the  flame.     The  flame  proper 

raises  the  temperature  of  the  metal  far  aborfhe 

melting  point;  the  excess  oxygen  furnished  b^  tJe 

burned,  not  melted,  away.     The  cutting  speed  and 
the  penetration  of  these  torches  is  remarkable      ^r> 
oxy-acetylene  torch  will  cut  steel  12  to  iTinche   'thifk 
and  a  hydrogen  torch  has  cut  metal  24  inches  tW,' 

tion  are    re™   r'^  °'  ^"  oxy-acetylene  installa- 
non  are  the  apparatus  generating  or  storing  oxygen 

^a   corpoVnH  !r't""'-   f ''*^'^"^  ^««  i«  «  "hemi- 

the  reactrbefw  ?  '"'*  ^^^'•°^^"'  ^^^^^  ^^om 

eii™  carbTde  ^Tr         T  '''^'^'  ""*^  ^^t^^'  ^al- 
um carbide  Itself  IS  not  explosive  when  drv      It 

"as,  however,  a  great  affinity  for  moisture    JZi  fi 
.as  generated  is  explosive.    I't  is  therete  'storedt 


132 


THE  MECHANICAL  EQUIPMENT 


air-tight  cans.  For  large  plants  the  oxygen  may  be 
generated  profitably,  but  for  small  plants  and  port- 
able work  it  is  purchased  in  steel  tanks.  The  acety- 
lene is  generated  in  small  quantities  as  used.  The 
generator  is  a  steel  receptacle  for  holding  the  gas, 
with  various  attachments  for  controlling  the  action 
of  the  water  on  the  carbide. 

The  hydrogen  used  in  oxy-hydrogen  flames  may  be 
obtained  from  the  decomposition  of  water  into  oxy- 
gen and  hydrogen,  both  gases  being  collected  and 
used,  or  it  may  be  formed  by  passing  steam  over 
coke.  It  is,  however,  usually  purchased  in  heavily 
charged  tanks.  The  oxygen  used  is  produced  com- 
mercially by  three  methods:  from  the  air,  by  liqui- 
faction  and  distillation;  from  water,  by  electrolytic 
action;  and  from  potassium  chlorate.  The  first  of 
these  methods  is  the  most  important  commercially. 
Although  the  production  of  oxygen  is  not  a  compli- 
cated process,  the  apparatus  is  rather  expensive  and 
its  use  is  justified  only  when  the  quantities  used  are 
rather  large.  Oxygen  is  sold  in  tanks  containing  5, 
25,  50  and  100  cubic  feet. 

Two  kinds  of  acetylene  generators  are  used,  known 
as  the  water-to-carbide,  or  water  feed,  and  the  car- 
bide-to-water, or  carbide  feed.  The  first  is  little  used, 
because  the  apparatus  may  get  hot  and  be  a  source 
of  danger.  When  the  second  method  is  used,  pow- 
dered or  granular  carbide  is  dropped  into  the  water; 
the  gas  is  washed  as  it  is  evolved,  and  the  apparatus 
is  kept  cool.  Furthermore,  water-feed  generators  give 
off  gas  long  after  the  water  is  stopped,  but  the  car- 
bide feed  gives  off  gas  only  for  a  short  time  after- 


WELDING,  SOLDERING,  BRAZING  133 

ward.  GeneraJIy  about  a  gallon  of  water  is  used  for 
each  pound  of  carbid^ne  pound  of  lump  carbide 
will  generate  41/2  cubic  feet  of  gas 

.rttlTT'-~'^^'  advantages  of  gas-flame  welding 
are  that  the  apparatus  required  may  be  either  light 
and  easily  portable,  or  may  be  installed  permanenfly 
For  repair  work,  the  gas  flame  shows  low  cost  and 
^celent  results.  The  improved  methods  of  controll- 
ing and  guiding  the  flame  have  extended  the  use  to 
manufacturing  work,  in  which  it  is  compeLrac 

hJatVtt  t  ^'^"""^  P™^^^^-    ^-'^^  t'  ^«  higt 

once  ff  5        7'  T^  ™'*^^  "^°  ^'  ™«"ed  locally  at 

those  of  frf\  ■^''  disadvantages   are  similar  to 

e„,  12  *^!,t'*"'  ^'''  ^°  *^^*  «  ^J^i'l^d  operator  is 

teTh  i:?f^''  "?*  "''  "  """"^  ^°^  sl--«  to  pro- 
tect himself  from  the  intense  brightness  of  the  in 

meuT?-  V-  ^-t^^™-.  as  the  weld  is  a' 
o'xldaS  "  *'^  ''^"  ""'' ''  "^  ^"^^--^  *«  --  or  less 
^rZ^'l'^^^  gas  flame  is  used  for  welding  wrought 

and  steerl^r'r^^l'"  ""  ^^^'  ^^  ''^^^^  on  iron 

b  lot  il/     •    I  '*  ^^'  ^'^°  ^PPli^d  successfully 
in  spot  welding  m  the  manufacture  of  metal  goods    It 

has  been  widely  used  in  cutting  work  of  evfrTkln? 

S  In  ki'nds    '°^  ""*  ''''^'  '"^  ^'""^  ^^'^^S«  ^ork 

by^rTl^?**-^-"^"'"'"^*  ^«'^^"g  ^as  invented 
^y  13r.  Goldschmidt,  of  Essen,  Germany.    By  this  nro 

tiie  parts  to  be  joined,  and  finely  divided  iron  oxide 


I 


:«.!<' 
,,jjii. 


4 


'^1 


134 


THE  MECHANICAL  EQUIPMENT 


and  powdered  aluminum  are  poured  into  the  mold  and 
burned.  A  chemical  reaction  follows  which  produces 
pure  iron  and  aluminum  oxide.  The  temperature  of 
the  reaction  is  about  5400  degrees  Fahrenheit,  or 
nearly  2000  degrees  above  the  melting  point  of  iron 
and  steel.  The  iron  formed  by  the  reaction  makes  a 
superheated  bath  around  the  joint.  The  ends  of  the 
work  which  are  to  be  joined  are  therefore  melted,  and 
fuse  with  the  molten  metal  in  the  mold,  while  the 
aluminum  oxide  formed  rises  to  the  top  of  the  molten 
mass  and  is  skimmed  off.  When  the  reaction  is  over, 
the  whole  cools  into  a  solid  mass. 

The  thermit  process  is  obviously  applicable  only  to 
iron  and  steel,  as  it  involves  a  chemical  reaction  with 
iron.  Its  advantages  may  be  summed  up  as  follows: 
first,  the  apparatus  is  simple;  second,  high  skill  is 
not  needed  to  do  the  work;  third,  it  is  possible  to  re- 
pair breaks  difficult  of  access  and  to  mend  broken 
parts  where  they  are  which  otherwise  would  have  to 
be  taken  out;  fourth,  local  heating  is  possible  on  a 
larger  scale  than  is  possible  with  the  gas  flame.  The 
thermit  process  has  been  used  successfully  in  welding 
rail  joints,  and  forms  of  molds  have  been  developed 
specially  adapted  to  that  work.  The  process  is 
adapted  only  to  rough  and  large  work,  and  is  too 
cumbersome  for  general  use  in  manufacture  where 
the  Thomson  process  and  the  gas  flame  have  been 
successful.  For  pieces  below  four  square  inches  in 
cross  section,  other  processes  are  better.  Some  won- 
derful repair  work  has  been  done  with  this  process 
in  the  welding  of  ship  frames,  rudder  posts,  and  so 
on.     The  breaking  strength  of  a  thermit  weld  runs 


WELDING,  SOLDERING,  BRAZING  135 

about  60,000  pounds  a  square  inch.  If  the  reinforce- 
ment  can  be  left  on  the  weld,  it  will  have  a  greater 
strength  than  the  original  material;  if  it  is  ma^chined 

sttngth''  '^'"'  ^^^''  """*  "^  ^^'  ^^i^i^-1 

for^tJT''^  ^^  Brazing.-Soldering  and  brazing  dif- 

0    tie  sold  Tl'  '^'  '''''''     ^^^  ^^^^^i^l  ^^^^ 

tor  the  solder  must  be  such  as  will  actually  wet  the 

surfaces  or  amalgamate  with  the  pieces  to  be  joined 

An  alloy  of  lead  and  tin  is  generally  used,  althTgh 

special  solders  are  made  without  either  of  them.    Sol-" 

on'lf  ir      Z  "'!  "'  ^'^'^^  ^'  ^^^^^^  ^^  brazed 
ones,  because  the  strength  is  limited  to  that  of  the 

t*"f  hr\f '^'  "f  .'  ^^  ''^'''  ^'-^y^  ^--  than 

iea    LT  'S''  ""'^'^     ^^'  P^^^^^«  ^^^^i-^«  less 
heat  than  welding  or  brazing,  is  easily  performed, 

and  requires  almost  no  apparatus.    An  ordinary  gas 

flame  or  blow  pipe  may  be  used.    For  work  of  mS 

erate  size  a  gasolene  or  kerosene  torch  may  be  em- 

nZttT  'T.'"^  r^  '''  frequently'used  for 
running  m  the  solder.    The  common  fluxes  are  sal 

and  borax.  These  are  used  to  dissolve  any  grease 
and  to  remove  any  oxide  present,  and  they  leave  a 
^tTborttn  .'"  ^'^  '""''^^  '^  ^^*-    Most  Ll^rs^^^^^^^ 

procei  'T  i  ^^'^'  ^^^  ^'^'''''    The  soldering 

process  consists  of  scraping  the  surfaces  clean,  heat 

m!2'l^^^^^  temperature  by  any  s;itablL 

soSer%  rf/  ^.^'  '"'^^'''  *^  ^'  ^'^^"^^^  melting  the 
solder  into  the  joint,  and  finishing  off  the  joint  after 


■'!!, 


136 


THE  MECHANICAL  EQUIPMENT 


it  has  cooled.  The  most  important  requirements  are 
to  watch  the  temperature  and  the  flux.  Too  high  heat 
causes  oxidation  and  makes  the  solder  run  too  freely; 
poor  fluxing  prevents  the  solder  from  amalgamating 
with  the  pieces  to  be  joined.  Nearly  all  the  metals 
except  aluminum  are  soldered  commercially.  The 
process  is  used  only  for  small  work  and  on  joints 
which  do  not  have  to  carry  a  heavy  strain. 

Bra^ng  Process. — This  process  is  similar  to  solder- 
ing, the  main  difference  being  the  use  of  a  harder 
filling  material,  which  requires  a  higher  melting  tem- 
perature. Iron,  copper,  and  brass  may  be  brazed. 
Brazing  alloys— or  spelters,  as  they  are  called— are 
mixtures  of  copper,  zinc,  and  tin.  The  composition 
varies  with  the  nature  of  the  work;  the  hard  spelters 
give  a  stronger  joint,  but  require  a  higher  tempera- 
ture. The  flux  used  is  made  of  borax  or  boracic  acid, 
and  the  heating  apparatus  usually  takes  the  form 
of  a  gasolene  or  kerosene  torch  for  small  and  moder- 
ate-sized work.  A  blacksmith 's  fire  may  be  used,  but 
care  must  be  taken  to  keep  the  parts  from  touching 
the  fuel,  and  a  reducing  flame  is  necessary  since  the 
work  is  done  at  high  temperature.  Iron  and  steel 
require  a  high  heat,  for  which  a  blue  Bunsen  flame 
is  generally  used. 

In  brazing,  the  surfaces  must  be  cleaned  by  scrap- 
ing, washing  and  brushing,  then  the  flux  is  applied, 
and  the  pieces  are  clamped  in  position  ready  for  join- 
ing. The  heating  should  be  gradual  and  well  distrib- 
uted. The  spelter,  which  is  melted  in  when  the  proper 
temperature  is  reached,  will  flow  into  the  space  left 
between  the  parts  and  make  a  tight  joint.    After  the 


WELDING,  SOLDERING,  BRAZING  137 

operation  is  completed,  the  pieces  should  be  allowed 
to  cool  slowly.    For  large  quantities  of  work,  immer- 
sion  brazing  is  used,  which  consists  in  cleaning  and 
fluxmg  the  parts,  clamping  them  together,  and  dip- 
pmg  them  into  a  tank  of  molten  spelter.     Brazed 
joints,  when  well  made,  may  be  as  strong  as  the  orig- 
inal metal   and  while  they  are  not  so  good  as  welds 
they  are  cheaper  and  easier  to  make.    When  used  in 
manufacturing  processes,  special  holding  devices  may 
be  employed,  which  greatly  facilitate  the  work.    Braz- 
ing is  used  widely  for  small  joints,  and  is  a  reliable 
commercial  process.  ^^uaoie 


Am 


lit 


I        ,  .   .   I; 


i. 


. 


CHAPTER  X 
HEAT  TREATAIENTS 

Variability  of  Steel  Properties.— The  physical  prop- 
erties  of  steel,  such  as  hardness,  strength,  and  tough- 
ness, may  be  varied  to  suit  particular  needs  to  a  de- 
gree possible  with  no  other  material.  We  are  so  used 
to  the  marvel  of  easily  and  accurately  cutting  a  piece 
of  steel  -with  an  edged  tool  made  from  the  same  bar 
that  we  do  not  appreciate  it.  A  railroad  rail,  the 
rudder  post  of  an  ocean  liner,  a  watch  spring,  and  a 
razor  are  composed,  in  the  main,  of  the  same  material. 
The  difference  in  their  properties  is  due  to  the  pres- 
ence of  certain  alloying  constituents  and  to  the  heat 
treatment  to  which  they  may  have  been  subjected. 
These  two  factors  are  closely  inter-related.  Heat 
treatment  consists  of  heating  and  cooling  the  metal 
through  certain  temperature  ranges  and  with  certain 
rates  of  temperature  change.  Of  the  various  metallic 
materials,  steel  offers  the  widest  variation  of  physical 
properties  through  heat  treatment.  The  capacity  so 
to  manipulate  it  depends  upon  both  the  kind  and  the 
percentage  of  alloying  constituents.  Pure  iron  cannot 
be  hardened. 

The  principal  alloying  element  in  steel  is  carbon, 
and  steels  which  contain  only  carbon  as  a  useful  ele- 
ment are  called  carbon  steels.    The  percentage  of  car- 

138 


.      .  HEAT  TREATMENTS  139 

bon  present  forms  the  basis  for  commercial  classifica- 
tion.   Below  0.15  per  cent  the  material  may  be  either 
steel  or  wrought  iron,  according  to  whether  it  was,  or 
was  not,  molten  in  the  early  stage  of  its  manufacture. 
Steel  which  contains  from  0.15  to  0.35  per  cent  of 
carbon  is  known  as  machinery  steel;  from  0.35  to  0  60 
per  cent,  as  open-hearth  steel;  and  from  0.60  per  cent 
up  to  a  maximum  of  2  per  cent,  as  crucible  or  too) 
steel.    Other  elements— such  as  sulphur,  phosphorus, 
and  sihcon-may  be  present  in  small  quantities,  but 
constitute  undesirable  impurities.    Manganese  is  also 
present,  and  up  to  a  certain  limited  percentage  is  a 
desirable  element.     Carbon  steels  are  referred  to  as 
twenty  point  or  thirty  point,  according  to  the  number 
ot  hundredths  of  one  per  cent  of  carbon  present     In 
general  the  strength  of  steel  rises  with  the  increase 
m  the  carbon.    Ten-point  steel  is  nearly  25  per  cent 
stronger  than  pure  iron,  and  through  a  considerable 
range  the  tensile  strength  rises  about  214  per  cent  for 
each  point  of  carbon  added.    Of  recent  years  there 
has  been  rapid  development  of  steels  known  as  high- 
speed steels,  for  cutting  purposes,  which  derive  their 
properties  from  the  addition  of  other  elements,  such 
as  chromium,  tungsten,  vanadium,  molybdenum,  man- 
ganese, and  nickel.    Since,  however,  their  composition 
and  treatment  are  too  complex  to  be  discussed  here, 
this  discussion  will  be  confined  mainly  to  a  consider- 
ation of  carbon  steel. 

Heat  Treat   Processes.-There   are   the  following 
tour  well-known  forms  of  heat  treatment: 

1-    Hardening,  which  consists  of  heating  the  steel 


140 


THE  MECHANICAL  EQUIPMENT 


to  a  certain  temperature  and  quenching  it  sud- 
denly in  some  cooling  medium.  This  process  is 
used  to  produce  very  hard  wearing  surfaces, 
and  the  cutting  edges  of  tools. 

2.  Annealing,  which  is  similar  to  hardening,  ex- 
cept that  the  steel  is  cooled  slowly  instead  of 
suddenly.  It  is  used  to  relieve  internal  stress 
due  to  cooling  or  mechanical  working,  to  pro- 
duce soft  steel  suitable  for  machining,  and  to 
restore  fine  grain  to  steel  which  has  been  coars- 
ened by  overheating. 

3.  Tempering,  which  consists  in  reheating  hard- 
ened  steel  to  a  certain  temperature,  much  below 
that  used  in  hardening  or  annealing,  for  the 
purpose  of  partially  restoring  its  ductility  and 
softness.  The  rate  of  cooling  is  unimportant. 
This  process  is  used  to  produce  a  desired  de- 
gree of  toughness  and  hardness,  and  to  raise 
the  elastic  limit  to  permit  large  deformations 
without  permanent  set,  as  in  springs. 

These  three  processes  act  through  temperature 
changes  merely  to  alter  the  molecular  condition  of 
the  steel  without  varying  the  total  carbon  content. 
To  these  may  be  added  a  fourth  closely  allied  process: 

4.  Case-Hardening,  which  consists  of  raising  the 
carbon  content  of  the  surface  of  low  carbon 
steel  so  that  it  can  be  hardened,  annealed,  or 
tempered  like  a  high  carbon  steel. 

Bardeningf. — The  hardening  of  carbon  steel  is  due 
to  a  change  of  internal  structure  which  takes  place 


HEAT  TREATMENTS  141 

when  it  is  heated  properly  to  a  definite  temperature. 
Ihis  temperature  varies  with  different  steels.  The 
process  is  applicable  only  to  those  having  more  than 
a20  per  cent  of  carbon,  and  is  usually  confined  to 
those  m  the  neighborhood  of  1.0  per  cent.  To  under- 
stand the  process  it  is  necessary  to  glance  at  what 
happens  to  the  internal  structure  of  steel  when  it  is 
heated  and  cooled. 

In  steel  at  normal  temperatures  the  chief  hardening 

knor:f  "1-?'  Tr ''  ^  p^^* ''  -  --titrnf 

known  as  pearlite.     If  heated  to  a  certain  critical 
empei^ture  the  pearlite  takes  another  f 0  m  k^own 
as  a^steni  e,  which  gives  steel  its  hardening  prop 
erty.    If  a  lowed  to  cool  slowly  from  this  temperature 
the  a^stenite  changes  back  again  to  pearlite,Vd  the 
el  becomes  soft  again.    In  Figure  30,  the  horizon! 

SeflVrr""^'  ?^^'  '^^'''^  '^  a' specimen  of 
steel   and  the  vertical  scale  the  rise  in  temperature 

The  heat,  when  first  applied,  all  goes  into  rafs^g  the 

temperature  of  the  piece  until  about  1350  Te|ree 

b^  act?allvTT''''t  ^^"'  ""''  ^"^^  ''^^'^  '^  ri«e, 
out  actually  falls  as  heat  is  added.     This  critiea 

e?S  e^^^^^  '^^^^^^--^  point  anTv! 

^es  with  each  kind  of  steel.    The  heat  expended  goes, 
not  into  raismg  the  temperature  of  the  piece  but  into 

ro  "?  1>  r '"^"^  ^^^  ^"*^™^  nioEa^^^^^^^^^^ 
from  pearhte  to  austenite.    Since  all  the  heat  is  goiS 

u  e  TSh  "  TV"'''  ''  ^^^^  ^  ^^"  -  tempera 
ture,  which  IS  due  to  surface  radiation.     After  the 

change  IS  complete,  any  further  heat  added  goes  into 
raising  the  temperature  until  the  final  point  is'reaeS 


f 


I 


I 


142 


THE  MECHANICAL  EQUIPMENT 


1700 

r 

— 

I 

1500 

\ 

■  t?or'/yl  ^K^^nr'O    — 

R- 

1 

\ 

.'      Point  about  IZIS"* 

^•1300 

f — *-| 1 1 1     ^ 

I     becalescence 

\           n     '     J,        L A    i-rr/^0 

\ 

—  r 

v/fff. 

aovi 

41    /J 

JV/ 

\ 

^1100 

• 

III 

< 

5)    900 

> 

> 

S  1 

...  \o 

^1 

K    1 
t    1 

<    700 
a: 

\  r 

:» 

0. 

1"   /N^N 

1 

uj    500 

/ 

\ 

• 

/ 

\ 

3  00 

/ 

\ 

/ 

\ 

lOO 

\ 

\ 

HEAT    SCALE 


FIG.    30.      HEAT-TEMPERATURE    CURVE 

If  at  this  point  the  piece  should  be  cooled  slowly, 
heat  is  radiated  away  and  the  temperature  falls 
until  another  point  of  inflection,  called  the  recal- 
escenee  point,  is  reached.  In  general,  this  will  be 
somewhat  lower  than  the  decalescence  point.  Here 
the  condition  of  the  carbon  is  changed  back  to  pearl- 
ite,  and  the  energy  previously  absorbed  is  converted 


HEAT  TREATMENTS  143 

back  into  heat.    After  this  second  change  is  complete, 
the  cooling  is  resumed  until  the  final  temperature  is 
reached.     The  change  at  the  recalescence  point  re- 
quires a  certain  time.     If,  instead  of  being  cooled 
slowly,    the   steel    is    quenched    suddenly    by   being 
plunged  into  a  cold  bath,  it  passes  through  a  compli- 
cated structural  rearrangement,  but  does  not  return 
fully  to  pearlite,  the  soft  form.    Tlie  piece,  when  com- 
pletely cooled,  will  be  very  hard  and  brittle,  and  the 
tensile  strength  and  elastic  limit  will  have  been  raised. 
The  hardness  obtained  will  vary  with  the  carbon 
content  and  the  suddenness  of  the  cooling.    The  cor- 
rect hardening  temperature  is  the  lowest  possible  one 
above  the  decalescence  point  which  will  make  sure 
that  the  steel  has  been  completely  changed  into  aus- 
tenite.    If  heated  considerably  beyond  this  point  the 
grain  will  be  coarsened  and  the  steel  will  be  burned 
or  oxidized.    The  danger  of  this  is  greater  the  higher 
the  carbon  content.    The  interesting  fact  that  steel, 
when  heated  beyond   this  critical   temperature,   be- 
comes non-magnetic  may  be  made  use  of  in  deter- 
mining the  decalescence  point.    The  composition  of 
the  quenching   bath   varies   for   different   purposes, 
brine,  oil  and  water  being  most  used,  and  the  degree 
ot  hardness  obtained  by  quenching  from  the  same 
temperature  is  greatest  with  brine,  less  with  water, 
still   less   with    oil.    This    is    probably   due   to   the 
rapidity  with  which  the  several  liquids  will  absorb  the 
fteat.    The  above  process  of  heating  and  quenching 
suddenly   ,s   used   for  hardening  all   carbon   steels, 
^elt-hardenmg  or  air-hardening  steels,  however,  are 
hardened  by  slow  cooling. 


144 


THE  MECHANICAL  EQUIPMENT 


HEAT  TREATMENTS 


145 


Heating.— Carbon  steels  should  be  heated  slowly 
and  evenly  to  the  right  temperature,  kept  from  con- 
tact with  air  to  avoid  oxidation,  and  always  quenched 
from  a  rising,  not  a  falling,  heat.  Care  should  be 
used  not  to  overheat  any  cutting  edges  and  corners 
before  the  body  of  the  material  is  brought  up  to  the 
right  heat.  It  is  obvious  that  unevenness  of  tempera- 
ture will  cause  a  variation  in  hardness. 

One  of  the  common  methods  of  heating  is  to  use 
a  bath  of  molten  lead,  potassium  cyanide,  or  barium 
chloride.  Care  must  be  exercised  in  using  these  baths 
to  have  the  piece  absolutely  dry  before  immersing  it. 
The  slightest  moisture  will  cause  the  molten  liquid  to 
fly  in  all  directions  and  burn  the  operator.  The  safest 
method  is  to  heat  the  piece  beforehand  sufficiently  to 
insure  its  being  perfectly  dry.  At  temperatures  above 
1200  degrees  Fahrenheit  lead  gives  off  a  poisonous 
vapor,  and  cyanide  of  potassium,  as  is  well  known,  is 
an  active  poison.  The  furnaces  used  for  heating  these 
baths  should  be  carefully  guarded,  and  should  be 
equipped  with  hoods  to  carry  away  the  fumes.  Pow- 
dered charcoal  is  often  floated  as  a  purifier  on  the  top 
of  the  molten  liquid. 

Of  the  various  baths,  the  lead  bath  is  most  used. 
It  is  especially  adapted  for  heating  small  pieces  that 
are  hardened  in  quantities.  The  lead  used  should  be 
pure,  and  free  from  sulphur.  Various  paints  and 
pastes  are  used  to  prevent  the  lead  from  sticking  to 
the  work,  or  the  piece  may  be  heated  and  dipped  into 
salt  water  just  before  immersion  in  the  bath.  Steel 
melting  pots  last  much  longer  than  those  made  of 
cast  iron  when  the  lead  bath  is  used. 


The   potassium   cyanide   bath   is   much   used   for 
cutting  tools,  for  dies,  and  in  gun  shops  for  color 
effects.    The  barium  chloride  bath,  which  has  a  high 
temperature,  (about  2200  degrees  Fahrenheit)  is  used 
to  some  extent  with  high-speed  steels.    The  pieces  are 
usually  pre-heated  in  a  gas  furnace  to  a  dull  red  in 
order  to  save  time  in  the  bath.    For  the  lower  tem- 
peratures required  for  carbon  steels— about  1400  de- 
grees— barium  chloride  and  potassium  chloride  are 
mixed  in  the  proportion  of  three  to  two.     Tempera- 
tures below  1075  degrees  are  obtained  by  mixing 
equal  parts  of  potassium  nitrate  and  sodium  nitrate. 
This  mixture  is  used  mainly  as  a  tempering  bath. 

Modern  heating  furnaces  are  ordinarily  oil  or  gas 
fired.  Many  types  are  on  the  market  especially 
adapted  for  various  sizes  and  kinds  of  products  The 
simplest  type  of  gas  furnace  is  a  plain,  circular  pot 
of  refractory  material,  as  shown  in  Figure  31.  Gas  in 
general  is  a  cleaner  fuel  than  oil,  but  is  more  expen- 
sive. Where  oxidation  is  objectionable,  muffles  or 
refractory  retorts  are  used.  Oil  is  the  cheapest  of  all 
the  fuels  for  large  work.  It  is  pumped  under  pres- 
sure to  the  furnaces  from  an  underground  tank,  atom- 
ized m  a  suitable  burner,  and  mixed  with  a  proper 
proportion  in  air.  Often  a  jet  of  steam  is  used  which 
impinges  on  the  hot  brickwork  of  the  furnace  and 
IS  broken  up  into  hydrogen  and  oxygen-both  gases 
jelp  m  the  combustion.    Large  heating  furnaces  are 

eniL''^       ..  ''^  ^""^  refractory  linings,  and  are 
equipped  with  pyrometers  to  aid  in  controlling  the 
temperatures.     Coal  and  coke  are  inferior  as  fuels 
as  they  are  dirtier,  the  temperature  control  is  more 


is 


Il 


146 


THE  MECHANICAL  EQUIPMENT 


HEAT  TREATMENTS 


147 


ii 


! 


PIG.    31.      SIMPLEST   TYPE  OP   CRUCIBLE   GAS-FIRED 

HEATING   FURNACE 


difficult,  they  require  more  labor  in  attendance,  and 
the  sulphur  and  other  impurities  are  more  or  less  ab- 
sorbed by  the  steel  being  heated. 

Quenching.— The  hardening  obtained  by  quenching 
will  vary  with  the  temperature,  mass,  and  conductiv- 
ity of  the  cooling  medium.     The  degree  of  hardness 
obtained  with  various  baths  in  0.90-  to  1.0-point  car- 
bon steel  ranges  in  the  following  order:     mercury, 
carbonate  of  lime,  brine,  pure  water,  soap  water,  milk, 
oils,  tallow,  and  wax.     These  different  materials  are 
used  for  different  purposes.    Oil,  having  a  lower  vis- 
cosity and  heat-carrying  capacity,  cools  the  steel  com- 
paratively slowly.     It  is   therefore   used   when   the 
piece  is  to  be  tough  rather  than  very  hard.    Water, 
being  higher  in  heat-carrying  capacity,  cools  the  steel ' 
more  quickly,  making  it  harder  and  brittle.     Brine 
makes  it  still  harder.     For  excessively  hard  work, 
quicksilver  is  sometimes  used.    Delicate  and  compli- 
cated pieces  cannot  be  cooled  in  brine  without  danger 
of  warping  and  cracking. 

The  temperature  of  the  bath  is  important,  as  water, 
for  instance,  at  60  degrees  will  give  a  greater  hard- 
ness than  water  at  150  degrees.  A  large  body  of 
liquid  is  better  than  a  small  one,  because  the  heat 
given  out  by  the  steel  will  raise  the  temperature  of 
a  small  bath  where  it  will  have  no  appreciable  effect 
on  a  large  one;  and  the  capacity  to  carry  away  heat 
IS  increased  if  the  liquid  is  in  circulation.  Clear 
water  is  generally  used  for  ordinary  carbon  steel, 
sperm  or  lard  oil  for  springs,  and  linseed  oil  for  cut- 
ters and  other  small  tools.  Certain  portions  of  an 
article  may  be  hardened  more  than  the  rest  of  it  by 


n 


148 


THE  MECHANICAL  EQUIPMENT 


having  cool  jets  of  the  quenching  liquid  impinge  on 
the  surface  at  these  points.  This  method  is  used  for 
hardening  the  face  of  forging  dies,  by  immersing  them 
face  downward  into  the  quenching  bath  and  causing 
a  jet  to  play  into  the  impressions.  In  cooling,  these 
impressions  will  become  harder  than  the  rest  of  the 
die. 

Skill  and  care  are  required  in  successful  quenching. 
The  pieces  should  not  be  thrown  in  carelessly,  be- 
cause unsymmetrical  cooling  will  cause  warping  and 
cracks  and,  even  if  these  do  not  develop,  will  pro- 
duce severe  internal  strains,  which  are  all  the  more 
dangerous  because  they  may  not  show  on  the  out- 
side. Even  with  the  best  of  care  warping  cannot 
'  be  wholly  obviated,  and  for  this  reason  very  accurate 
machined  pieces  must  be  ground  after  heat  treatment. 

There  are  a  number  of  rules  which  apply  generally. 
The  piece  should  be  stirred  in  the  bath  to  break  up 
the  coating  of  vapor  which  tends  to  gather  on  its  sur- 
face and  retard  the  rapidity  of  cooling.  Stirring 
also  serves  to  bring  the  piece  into  cooler  portions  of 
the  bath.  Long,  thin  pieces  should  be  quenched  in 
the  direction  of  the  principal  axis  of  symmetry,  to 
avoid  warping.  A  gear  wheel  should  be  hardened 
perpendicularly  to  its  plane,  and  a  shaft  vertically. 
Hollow  pieces  should  have  the  ends  plugged,  since 
otherwise  they  cannot  be  quenched  vertically  with- 
out the  formation  of  steam  inside.  When  pieces  have 
thick  and  thin  sections  the  thicker  portions  should 
be  immersed  first. 

Self-Hardening  Steels. — These  steels  are  obtained 
by  the  addition  of  chromium  and  other  elements,  as 


HEAT  TREATMENTS 


149 


already  mentioned.  The  proper  form  of  treatment 
varies  with  the  composition,  and  the  directions  given 
by  the  makers  should  be  followed.  Usually  they 
are  heated  to  a  red  heat  and  cooled  in  an  air  blast, 
or  dipped  in  oil.  It  is  not  necessary  to  draw  the 
temper.  Great  care  is  required  in  heating  them  for 
forging,  since  the  forging  heat  has  a  very  narrow  range 
of  temperature  and  they  may  be  very  easily  spoiled. 
Some  grades  of  self -hardening  steel  may  be  annealed 
by  heating  to  a  bright  heat  in  the  centre  of  a  good 
forge  fire  and  allowing  the  fire  to  die  out,  the  fire  and 
the  steel  cooling  off  together.  Steel  so  annealed  may 
be  hardened  again  by  heating  to  the  hardening  heat 
and  cooling  in  oil. 

Taylor- White  Steel.— This  type  of  steel  should  be 
heated  slowly  to  red  heat  and  then,  as  quickly  as 
possible,  to  a  temperature  just  short  of  the  melting 
point,  when  it  begins  to  show  signs  of  softening.    It 
should  then  be  cooled  suddenly  in  oil  to  a  low  red 
heat.    From  then  on  the  cooling  may  be  either  fast  or 
slow,  down  to  the  temperature  of  the  air.     Taylor- 
White,  or  high-speed  steel,  is  no  harder  than  hardened 
carbon  steel.    It  has,  however,  the  remarkable  qual- 
ity of  **red  hardness;''  that  is,  the  steel  remains  hard 
even  at  a  red  heat,  which  corresponds  to  something 
over  1000  degrees  Fahrenheit,  while  ordinary  carbon 
steels  begin  to  soften  at  about  390  degrees  and  lose 
all  of  their  hardness  when  heated  to  about  700  de- 
grees.   The  larger  part  of  the  work  done  by  a  cutting 
tool  goes  into  heating  the  object  cut,  the  chip  and  the 
pomt  of  the  tool.     In  continuous,  heavy  cutting  at 
high  speed,  that  portion  of  the  heat  entering  the  too] 


ill 


150 


THE  MECHANICAL  EQUIPMENT 


will  raise  the  temperature  high  enough  to  draw  the 
temper  of  carbon  steel.  When  this  occurs  the  tool 
begins  to  soften,  the  edge  is  lost,  and  the  cutting 
qualities  are  gone.  In  high-speed  steel  there  is  a 
leeway  of  more  than  600  degrees  before  this  action 
takes  place,  and  consequently  much  higher  cutting 
speeds  and  heavier  cuts  are  possible  than  with  car- 
bon steels.. 

Annealing. — ^In  making  complex  steel  forgings  it 
is  impossible  to  heat  all  parts  alike.  Some  parts 
therefore  cool  from  a  higher  temperature  than  others. 
A  uniform  fine  grain  may  be  given  them  by  anneal- 
ing. Steel  castings  are  also  annealed  to  relieve  in- 
ternal strains  due  to  the  unequal  cooling  after  pour- 
ing, and  to  refine  the  grain.  The  steel  is  heated  to  a 
little  above  its  critical  temperature,  as  if  for  harden- 
ing, but  instead  of  being  cooled  suddenly,  it  is  al- 
lowed to  cool  from  this  temperature  very  slowly. 
When  this  is  done,  the  fine-grained  austenite  struc- 
ture has  time  to  readjust  itself  in  passing  the  recal- 
escence  point,  and  thereby  acquires  its  natural  pearl- 
ite  structure.  When  it  is  completely  cooled  it  will 
be  soft  and  tough. 

The  principal  difference  between  the  annealing  and 
the  hardening  process,  therefore,  is  the  substitution 
of  slow  cooling  for  sudden  quenching.  Steel,  to  be 
annealed,  should  be  packed  in  boxes  in  powdered 
charcoal  or  lime,  sealed  in  order  to  prevent  oxidation, 
and  heated  slowly.  Very  low  carbon  steel  should  be 
heated  to  about  1625  degrees  Fahrenheit,  and  high 
carbon  steel  to  1475  degrees.  The  heat  should  be 
held  there  long  enough  to  insure  an  even  temperature 


HEAT  TREATMENTS 


151 


throughout  the  piece  that  is  being  annealed.  As  with 
hardening,  the  piece  should  not  be  heated  much  be- 
yond the  critical  temperature.  If  this  is  done  the 
gram  is  coarsened  and  the  steel  may  be  decarbonized 
Slow  cooling  is  the  essential  feature  of  the  annealing 
process. 

Brass  and  copper  are  also  annealed.  When  these 
metals  have  been  drawn  or  rolled  to  more  than  a  cer- 
tain percentage  of  reduction,  they  become  hard  and 
brittle  and  will  split  on  further  working.  The  soft 
structure  may  be  restored  by  heating  them  to  a  dull 
red  heat  and  allowing  the  pieces  to  cool.  Unlike 
steel,  these  metals  may  be  cooled  suddenly  as  well  as 
slowlv. 

Tempering.— Tempering   is   a   secondary   process, 
coming  after  hardening,  and  the  reheating  is  always 
to  a  temperature  much  less  than  the  critical  or  hard- 
emng  temperature.    The  main  purpose  of  this  process 
IS  to  reduce  the  brittleness  and  increase  the  tough- 
ness, but  unfortunately  it  always  undoes  to  some  ex- 
tent the  work  of  hardening.    If  the  piece  is  reheated 
to  only  a  low  temperature,  most  of  the  hardness  and 
bnttleness  will  remain.    The  higher  the  temperature 
to  which  It  IS  heated,  the  more  of  these  qualities  will 
be  taken  out  until,  if  it  is  heated  to  above  the  critical 
temperature,   they  will   entirely  disappear  and   the 
tempering  process  will  have  become  annealing.    Cut- 
ting tools  should  always  be  left  as  hard  as  possible 
and  yet  tough  enough  for  the  work  intended 

The  Color  Scale.-When  hardened  steel  is  heated 
the  color  changes  with  the  rising  temperature  from' 
a  pale  yellow  through  a  darker  yellow  into  brown 


■J" 


I 


152  THE  MECHANICAL  EQUIPMENT 

brown-purple,  purple,  and  finally  to  a  dark  blue.  This 
color  scale  has  long  been  used  as  a  gauge  for  temper- 
atures in  tempering.  Its  use  requires  great  skill  and 
uniform  conditions  of  lighting,  and  so  on,  if  uniform 
results  are  to  be  obtained,  and  for  accurate  work  a 
pyrometer  should  be  used.  The  color  scale,  with  the 
corresponding  temperatures  and  the  class  of  tools  for 
which  they  are  used,  is  given  below. 


CoLOB  AND  Temperature  Scale  for  Tool  Hardening* 


Color 


Very  pale  yellow 

Light  yellow 
Pale  straw  yellow 
Straw  yellow 
Deep  straw  yellow 
Dark  yellow 
Yellow  brown 
Brown  yellow 
Spotted  brown 
Brown  purple 
Light  purple 
Full  purple 
Dark  purple 
Full  blue 
Dark  blue 


Degrees 


Fahr. 


430 

440 
450 
460 
470 
480 
490 
500 
510 
520 
530 
540 
550 
560 
570 


Cent. 


221 

227 
232 
238 
243 
249 
254 
260 
266 
271 
277 
282 
288 
293 
299 


Class  of  Tools 


Punches,  Scraping  Tools,  Draw- 
ing Dies 
Milling  Cutters,  Reamers 
Twist  Drills 
Counterbores 
Edging  Cutters 
Pipe  Cutters 

Knurling  Tools,  Pen  Knives 
Threading  Dies  and  Taps 
Cold  Chisels 
Small  Taps 

Dies  for  threading  to  a  shouUler 
Springs 

Molding  Cutters 
Wood  Saws 


Edged  tools,  such  as  chisels,  are  tempered  by  heat- 
ing the  cutting  end  to  a  cherry  red  and  then  quench- 
ing the  part  to  be  hardened.  When  the  tool  is  re- 
moved from  the  quenching  bath,  the  heat  remaining 
in  the  unquenched  part  of  the  tool  will  raise  the  tem- 


*This  table  is  compiled  from  Machinery's  Mechanical  Library, 
Vol.  VIII,  pp.  70  and  76,  and  Rose's  "Modern  Machine  Shop  Practice. 


HEAT  TREATMENTS  153 

perature  of  the  cutting  end  to  the  desired  color  when 
the  entire  tool  is  quenched.     The  modern  method  of 
tempering  in  quantity  is  to  heat  the  pieces  in  a  bath 
of  molten  lead,  heated  oil,  or  other  liquid,  the  tem- 
perature of  which  may  be  kept  within  very  close 
limits.    Beds  of  heated  sand  and  salt  are  also  used. 
The  use  of  baths  or  sand  beds  is  preferable  to  open 
heating  because  there  is  a  closer  control  of  the  tem- 
perature which  determines  the  degree  to  which  the 
tempering  is  carried.    High-speed  steel  does  not  re- 
quire tempering.    It  should  be  cooled  in  some  thin  oil, 
such  as  lard  or  paraffine.    If  paraffine  is  used  the 
piece  should  be  kept  under  the  surface  until  cooled  to 
the  temperature  of  the  bath;  otherwise  the  oil  will 
ignite. 

Carbonizingr.— Carbonizing  is  a  very  valuable  pro- 
cess for  a  good  many  classes  of  articles  in  which  the 
contradictory  qualities  of  toughness  and  hardness  are 
both  wanted.  Low-carbon  steel  is  tough,  but  cannot 
be  hardened.  High-carbon  steel  can  be  hardened,  but 
becomes  brittle  in  the  process.  Case-hardening  is 
simply  the  partial  carrying  out  of  the  old  cementation 
process  of  making  steel,  in  which  bars  of  wrought 
iron  were  heated  a  long  time  in  the  presence  of  car- 
bonaceous material,  and  the  carbon  given  off  was  ab- 
sorbed by  the  iron  until  its  carbon  content  was  raised 
to  the  point  desired  and  it  became  steel. 

In  case-hardening  the  process  is  carried  on  long 
enough  to  drive  the  carbon  in  to  the  depth  desired  A 
low-carbon  steel,  properly  packed  in  carbonaceous  ma- 
terial and  maintained  at  a  temperature  of  1650  de- 
grees Fahrenheit  for  about  two  hours,  will  be  changed 


I 


!!!, 


:|i 


>i 


\i 


I':  I 

it ' ' 


r 

"I 


154 


THE  MECHANICAL  EQUIPMENT 


I 


to  80  point  carbon  steel  to  a  depth  of  about  1/64  inch; 
heating  it  for  four  hours  will  case-harden  it  to  1/32 
inch,  and  the  carbon  will  be  1.0.  If  it  is  heated  for 
six  hours,  the  case-hardening  will  be  1/16  inch  deep 
and  the  carbon  content  1.15.  In  case-hardening,  the 
material  is  packed  in  cast-iron  boxes  or  pots  with  the 
carbonizing  material,  such  as  charcoal,  charred 
leather  scraps,  or  burnt  bone.  It  is  then  covered  and 
sealed.  A  number  of  case-hardening  compounds  are 
on  the  market  and  may  be  used  instead  of  the  ma- 
terials mentioned,  as  some  of  them  have  become  too 
valuable  for  general  case-hardening  work. 

If  the  piece  is  quenched  after  being  case-hardened, 
the  surface,  having  been  transformed  into  high-carbon 
steel,  will  become  hardened  to  the  depth  of  the  case- 
hardening,  and  the  soft  low  carbon  interior,  which 
cannot  be  hardened,  will  remain  tough.  The  article 
will  therefore  have  the  double  qualities  desired.  The 
**Harveyizing"  of  armor  plate  is  case-hardening  ap- 
plied on  a  large  scale.  Quenching  from  the  same  heat 
is  practiced  when  only  color  effects  and  a  hard  sur- 
face are  desired.  For  a  better  quality  of  temper  the 
piece  is  cooled  slowly,  and  hardened  after  a  subse- 
quent heating,  since  the  hardening  temperature  is  not 
so  high  as  the  case-hardening  temperature  and  a  sec- 
ond heating  gives  better  results. 


CHAPTER  XI 
THE  TOOL  ROOM— FIXTURES  AND  GAUGES 

The  Tool  Room  a  Modem  Development.— As  there 
will  be  no  frequent  references  in  the  chapters  dealing 
with  machine  tools  to  the  tool  room  and  to  tool-room 
methods,  it  is  well  to  consider  briefly  the  functions  of 
the  tool  room  and  the  part  they  play  in  machine- 
shop  methods.     The  tool  room  is  a  modern  develop- 
ment and  an  embodiment  of  the  principle  of  the  sub- 
division of  labor.    The  typical  figure  in  the  old-time 
machine  shop,  which  built  its  products  before  manu- 
facturing methods  became  general,  was  *'the  general 
all-round  mechanic."    He  was  a  man  of  skill  and  ex- 
perience.   He  ground  his  own  tools  to  suit  himself, 
and  sometimes  even  forged  them.    With  the  possible 
help  from  time  to  time  of  an  overdriven  foreman,  he 
decided  how  the  work  was  to  be  done,  set  the  work 
upon  the  lathe  or  planer,  and  measured  it  to  deter- 
mine the  setting  of  the  tools,  generally  using  his  own 
scales  and  small  tools  in  the  process.     Much  of  his 
time  went  into  work  that  could  be  done  by  a  less 
skilled  man,  and  his  measurements,  however  skillful, 
were  subject  to  more  or  less  variation. 

Relation  of  Tool  Room  to  Shop.— The  general  me- 
(•lianic   has   largely   disappeared   from   the   machine 
'ooms  of  the  modern  shop  that  turns  out  interchange- 
.    >    155    . 


"''ii 


156  THE  MECHANICAL  EQUIPMENT 

able  products.    His  work  has  been  split  up  into  that 
of  the  skilled  tool-maker  and  that  of  the  handy  man, 
or  machine  tender,  who  does  little  more  than  set  the 
work  into  a  fixture  and  tend  the  machine.    The  tool- 
maker  now  plans  the  operations,  makes  the  small-tool 
equipment  to  carry  them  out,  and  maintains  the  ma- 
chines  in  proper  condition.    The  tool  department  also 
sharpens  the  tools  and  takes  care  of  them,  issuing 
them  to  the  workmen  as  needed.    The  tool  room  car- 
ries  on  such  important  work  that  it  has  well  been 
called  '*the  heart  of  the  shop."    It  is  here  that  the 
quality  of  the  output  of  a  plant  is  set,  and  maintamed. 
A  good  tool  room  usually  implies  a  good  shop,  and 
a  good  shop  cannot  exist  if  there  is  a  poor  tool  room. 
The  quality  of  the  work  done  throughout  the  plant 
will  run  down  and  the  cost  of  production  go  up  un- 
der  the  following  conditions: 

a.  If  the  producing  machines  throughout  the  factory  are  not 
properly  equipped  with  the  necessary  fixtures  and  cut- 
ting tools.  . 

b     If  the  tool  equipment  is  not  maintained  in  good  condition. 

c  If  the  gauges  used  to  check  the  quality  of  the  product  are 
not  properly  designed,  well  made,  and  kept  in  repair. 

d.  If  the  tools,  fixtures,  and  gauges  are  not  at  all  times  ready 

for  use. 

e.  If  they  cannot  be  found  promptly  when  wanted. 

t     If  the  producing  machines  themselves  are  not  maintained 
in  good  repair.    Good  tool  equipment  on  a  worn-out 
machine  will  do  bad  work. 
Functions  of  the  Tool  Room.— The  foregoing  con- 
siderations determine  the  functions  of  the  tool  room, 
which  are  three  in  number. 

The  first  function  is  to  build  and  maintain  fixtures, 


FIXTURES  AND  GAUGES  157 

gauges,  special  machines  used  for  manufacture,  and 
such  small  tools  as  are  not  purchased  from  outside, 
ihis  cares  for  items  a,  b,  and  c,  and,  as  pointed  out 
m  a  previous  chapter,  involves  close  touch  with  both 
the  drafting  room  and  the  shop.     This  is  particu- 
larly  important  in  the  manufacture  of  interchange- 
able  products.    Some  shops  have  a  tool-room  commit- 
tee, analogous  to  the  design  committee  described  in 
Chapter  II.     Such  a  committee  is  composed  of  the 
tool-room  foreman,  the  principal  machine-room  fore- 
man, and  the  drafting-room  man  who  is  in  charge  of 
tool  design.    No  new  design  of  such  an  article  as  a 
gun  IS  complete  until  a  list  of  operations  giving  the 
number  and  order  of  operations  has  been  settled  upon, 
mcludmg  all  the  working  points,  as  they  are  called, 
which  are  the  points  or  surfaces  used  for  locating  the 
work  during  the  various  cutting  operations. 

Another  list  giving  the  sequence  of  the  gauffinff 
operations  and  their  relation  to  the  manufacturing 
operations  should  be  settled  upon  at  the  same  time. 
Ihese  are  necessary  before  any  work  can  be  intelli- 
gently  started   on   the   fixtures,   special   tools,   and 
gauges  which  are  to  be  built.    Before  these  lists  are 
determined  upon,  all  those  modifications  of  the  design 
ot  the  product  which  are  desirable  for  economy  in 
manufacture,  must  have  been  made.    Few  things  will 
demoralize  a  tool  room  more  completely  than  con- 
tinued tinkering  with  the  design  of  new  output  after 
work  has  been  started  on  the  tools. 

The  second  function  of  the  tool  room  is  to  sharpen 
and  grind  all  tools  and  maintain  them  in  proper  work- 
ing  condition.    There  is  a  right  and  best  way  to  grind 


158  THE  MECHANICAL  EQUIPMENT 

each  tool.  If  the  decision  of  this  question  is  left  to 
the  whim  or  fancy  of  each  machine  hand,  few  tools 
will  be  ground  properly  and  there  will  be  no  stand- 
ards of  tool  practice  in  the  shop.  Furthermore,  spe- 
cial tool-grinders  have  been  developed  which  not  only 
turn  out  correctly  ground  work,  but  enable  this  work 
to  be  done  by  labor  much  less  skilled  than  the  gen- 
eral mechanic. 

The  third  function  of  the  tool  room  is  to  store 
and  to  charge  out  the  small-tool  equipment  and  sup- 
plies to  the  workmen  as  needed.  This  is  done  by  a 
tool  storeroom,  which  may  or  may  not  be  a  part  of 
the  main  tool-room  organization. 

The  Tool  Storeroom. — The  functions  of  the  tool 
storeroom  are: 

a.  To  protect  tools  against  loss,  theft,  deterioration,  and  con- 

fusion. 

b.  To  provide  a  place  for  every  tool,  which  place  shall  be  re- 

served for  that  tool  and  identified  with  it.  ^ 
c    To  provide  means  for  locating  where  any  tool  is  when  it  is 
not  in  the  storeroom.     This  is  done  through  some  form 
of  check  system  or  its  equivalent. 

d.  To  show  what  tools  any  man  has  at  any  given  time. 

e.  To  maintain  records  covering  breakage,  wear,  and  so  on, 

which  will  furnish  a  basis  for  determination  of  tool 
costs. 
The  storage  facilities  should  be  as  simple  as  possible, 
should  conform  to  a  well  thought  out  plan,  and  should 
be  readily  intelligible,  economical  of  space,  and  capa- 
ble of  expansion. 

In  general,  the  tool-building  for  the  entire  plant 
may  be  centralized  in  one  room  or  department  for 
convenience  in  administration,  but  the  tool-grinding 


FIXTURES  AND  GAUGES  159 

and  tool-storage  may  sometimes  be  divided  to  ad- 
vantage and  carried  on  in  small  storerooms  about  the 
plant,  one  in  each  department— the  controlling  con- 
sideration would  be,  what  arrangement,  under  the 
given  conditions,  will  entail  the  fewest  steps  and  lea^t 
loss  of  time! 

Machine  Equipment.— The  machine  equipment  of 
the  tool  room  for  a  moderate-sized  plant  will  consist 
of  one  or  more  of  the  following  machines: 

High-class  lathes,  8  to  24  inches,  seldom  for  work  awev  6 
or  8  leet  long. 

Universd  milling  machines,  with  index  head,  etc. 

Horizontal  boring  mills. 

Die-sinking  machines. 

Planers,  moderate  size. 

Shapers. 

Drill  presses. 

Radial  drills. 

Precision  grinders,  for  surface  and  circular  work. 
Rough  grinders. 
Power  hack  saw. 

Full  equipment  of  standard  gauges  adapted  to  the  work  in 
hand,  such  as  plug  and  ring,  screw-thread  and  pipe 
gauges,  gauges  for  standard  tapers,  surface  plates, 
squares,  etc. 

These  machines  will  be  used  in  the  general  tool  room. 
To  these  may  be  added  drill  and  milling  cutter  grind- 
ers, lathe  and  planer  tool-grinders,  and  so  on,  which 
rnay  be  either  in  the  main  tool  room,  or  the  branch 
tool  rooms  if  there  are  any  throughout  the  plant.* 

..m   *^^^   ^^^   design    of   fixtures,    gauges,    and    special    tools,    see 
J^oois  and  Patterns,"  by  A.  A.  Dowd,  Factory  Management  Course. 


160  THE  MECHANICAL  EQUIPMENT 

PoUcies.-Certain  policies  are  desirable  in  tool-room 
practice.   Day  wages  prevail  because  of  the  variety  and 
accuracy  of  the  work.    In  making  tools  precision  ot 
workmanship  is  more  desirable  than  great  economy 
of  production.    The  tool-room  foreman  should  be  the 
best  man  obtainable.    The  best  is  not  too  good,  tor 
there  are  few  men  in  the  whole  plant  who  have 
greater  influence  on  the  quality  of  the  work  and  the 
cost  of  production.    If  the  tool  room  is  of  fairly  large 
size,  the  principles   of   standardization   can   always 
be   profitably    applied   on   such   details    as    cutters, 
shanks,  bushings,  tapers,  and  so  on.    Often  the  work 
may  be  subdivided  into  skilled  and  less  skilted  func- 
tions, and  the  workmen  may  be  chosen  accordingly. 
New  tools  and  fixtures  should  be  estimated  on,  the 
estimates  covering  the  anticipated  saving;  and  these 
estimates  should  be  checked  with  the  cost  of  the 
fixtures  and  the  actual  saving  in  output  reahzed. 
This  offers  one  of  the  few  checks  possible  on  the  work 

of  the  tool  room. 

Fixtures  and  Jigs.— A  fixture  may  be  defined  as  a 
device  for  locating  and  clamping  work  in  proper  po- 
sition for  a  machining  operation.  A  jig  is  a  device 
for  guiding  a  cutting  tool;  usually  it  is  combmed  with 
a  fixture.  These  terms  are  used  loosely  and  m  most 
shops  interchangeably,  but  properly  speaking  a  fix- 
ture relies  upon  the  machine  to  locate  and  guide  a 
cutting  tool  with  reference  to  the  work.  While  a 
jig  often  locates  and  clamps  the  work,  it  combines 
with  this  means  for  guiding  the  cutting  tool  during 
its  operation.  A  fixture  is  usually  clamped  firmly  to 
the  table  of  the  machine;  a  jig  is  usually  free  to  move 


FIXTURES  AND  GAUGES  161 

and  to  find  its  own  position,  as  in  the  case  of  a  drill- 
ing jig,  which  centers  itself  on  the  point  of  the  drill. 
1  shall  not  attempt  here  to  go  into  the  details  of  jig 
and  fixture  design,  but  shall  consider  merely  general 
principles,  partly  economic  and  partly  mechanical. 

Economic  Principles.-!.  The  jigs  and  fixtures 
should  be  suited  to  the  work.  This  is  not  so  obvious 
as  It  It  seems,  for  there  are  many  ways  of  doing  most 
operations  and  many  instruments  that  can  be  used, 
and  the  selection  of  the  best  ways  and  means  is  often 
a  matter  of  skill  and  experience. 

2.  They  should  not  be  idle  most  of  the  time. 
Sometimes  a  fixture  is  built  which  will  perform  an 
operation  in  one-half  or  one-third  of  the  time  required 
without  It,  but  the  total  money  value  represented  by 
the  saving  may  not  be  large  enough  to  justify  the  ex- 
pense. A  saving  of  5  per  cent  on  the  cost  of  a  much- 
used  operation  may  justify  a  greater  tool  expense  than 
a  saving  of  90  per  cent  on  another  operation  which 
goes  through  the  shop  only  occasionally. 

3.  Fixtures  should  show  an  adequate  return  on  the 
investment  through  the  saving  in  cost  of  operation,  or 
should  materially  improve  the  quality  of  the  output. 
Well-designed  fixtures  usually  do  both.  When  the 
post  of  the  fixtures  is  balanced  against  the  saving  in 
operation  cost,  the  wear  and  maintenance  of  the  fix- 
tures, which  is  usually  considerable,  must  be  taken 
into  account  and  charged  against  it. 

4.  Fixtures  should  be  arranged,  whenever  possi- 
ble, to  perform  simultaneous  operations.  This  not 
on  y  saves  cost  of  handling,  but  usually  increases  the 
accuracy  of  the  output. 


'11' 


:;*■ 


162  THE  MECHANICAL  EQUIPMENT 

Mechanical  Principles.-!.  Fixtures  should  be  firm 
enough  to  equal  the  stability  of  the  machine  and  the 
cutting  tool,  and  should  be  heavy  enough  to  preclude 

all  chattering. 

2  The  clamping  devices  should  be  rapid  in  action 
and  positive  in  locating  the  work.  The  clampmg  is 
usually  done  by  screws  and  nuts,  toggle  joints,  or 
cams.  In  general,  it  is  desirable,  whatever  the  clamp- 
ing device,  to  have  a  quick  motion  set  the  jaws  up  on 
the  work,  and  then  a  slow  movement  with  increased 
power  to  produce  the  clamping  effect. 

3  •  All  vises,  and  like  equipment  used  for  holding 
work  should  have  one  fixed  jaw,  and  the  rotation  of 
the  cutter  and  the  thrust  of  the  feed  should  be  against 

this  jaw.  ,      ,  «  ..  1, 

4  There  should  be  adherence  to  the  definite  work- 
ing'points  laid  out  in  the  list  of  operations.  If  pos- 
sible the  working  point  should  come  against  the  fixed 

jaw.  .     , 

5  Parts  which  locate  the  work  or  clamp  against 

it,  and  in  the  case  of  jigs  the  legs  also  which  bear 
on  the  drill-press  table,  should  be  tool-steel  hardened, 
or  machinerv  steel  case-hardened. 

6  There  should  be  clearance  in  the  corners  for 
dirt  and  for  burrs  left  from  any  previous  operation, 
as  well  as  ample  room  for  the  chips  to  get  away. 

7  All  wing  nuts,  handles,  levers,  and  so  on, 
should  be  made  large  enough  to  operate  with  a  mod- 
erate pressure.  If  this  is  done,  the  fixture  will  work 
faster  be  more  accurate,  and  last  longer  than  if  these 
parts  'were  skimped.  Wherever  the  workmen  is  ham- 
mering these  down  with  a  mallet  after  setting  them 


FIXTURES  AND  GAUGES  163 

np  by  hand,  he  is  losing  time  and  is  in  serious  danger 
of  springing  the  work,  or  the  fixture,  or  both. 

8  In  the  oase  of  multiple  fixtures,  avoid  stacking 
the  pie.'es  against  one  another.  Every  piece  should 
be  set  agaiHift  a  solid  stop. 

9.  In  the  designing  of  fixtures  for  formed  milling 
operations,  the  piece  should  be  so  positioned  that  the 
Tarious  sections  of  the  milling  cutter  will  be  as  nearly 
the  same-  diameter  as  possible. 

10  If  possible,  the  locating  points  should  be  so 
arranged  that  the  piece  cannot  be  placed  in  the  fix- 
ture in  a  wrong  position. 

11.  in  the  case  of  drilling  jigs  it  is  desirable  to 
have  four  legs  bearing  on  the  drill  table.  If  the  table 
IS  out  of  true,  or  if  one  of  the  legs  is  resting  upon  a 
chip,  the  rocking  of  the  jig  will  show  it.  A  three- 
legged  Jig,  like  a  three-legged  stool,  will  sit  firmly 
on  an  irregular  surface,  and  consequently  the  oper- 
ator will  not  detect  an  unevenness  that  will  be  shown 
up  by  a  four-legged  one. 

•  T^T  £''"o^^i"g  additional  points  are  brought  out 
m  A  Treatise  on  Milling  and  Milling  Machines"  by 
the  Cincinnati  Milling  Machine  Company: 

Doir.t'"' ntr^  ^^'"i'l- ^  immediately  above  the  supporting 
Hf  ?1  J?r^^''*^,°*,*'"'  ^^^^^  ^  springing  of  the  work,  or 
into  a  fulcram.  ^  '"^^*"^'  P"'"*  ^'""^  transformed 

fnr  J'""^*  ^^'^  srapporting  points  should  be  the  maximtnn 
lor  any  rough  surfaces. 

Supporting  points  for  finished  surfaces  should  be  as 
Hmaii  in  area  as  is  consistent  with  the  pressure  to  be  exerted 
oy  the  clamps. 


m 


164  THE  MECHANICAL  EQUIPMENT 

All  supporting  points  should  be  set  as  far  apart  as  the 
nature  of  the  work  will  allow. 

All  side  clamps  should  be  arranged  to  press  downward. 

The  fixed  supporting  points  should  always  circumscribe 
the  center  of  gravity  of  the  work.  ..,*!.« 

All  supporting  points  over  and  above  the  original  three 
shoiild  be  sensitive  in  their  adjustment. 

All  clamps  and  adjusting  support  should  be  operated 
from  the  front  of  the  fixture. 

All  clamps  and  support  points  that  are  operated  or 
locked  by  wrench  should  have  the  same  size  head. 

Support  points  should  be  set  so  ...  as  to  mmi- 
mize  the  amount  of  cleaning  required. 

Support  points  should  have  provision  for  easy  removing 
and  replacing  in  the  event  of  breakage. 

Fixed  support  points  should  have  provision  for  adjust- 
ments  to  take  care  of  variations  in  castings  from  time  to  time. 

Clamps  should  be  arranged  so  that  they  can  be  easily 
withdrawn  from  the  work.  This  is  to  avoid  lengthy  un- 
Tcrewlng  of  the  nut  in  order  to  give  ample  clearance  between 

clamp  and  work.  .    .   , 

Snrinffs  should  be  used  to  hold  clamp  up  against  clamping 
nut  This  is  to  avoid  the  falling  down  of  the  clamp  and  the 
c»ent  loss  of  time  attendant  on  holding  it  up  while  insert- 
ing  the  work  beneath. 

Supporting  points  and  clamps  to  be  accessible  to  the 
operator's  hand  and  eye.  ,      ^i.- 

Adequate  provision  for  taking  up  end  thrust  so  that  this 
will  not  be  dependent  upon  friction  between  work  and  clamp. 

All  of  the  above  axioms  are  applicable  to  almost  every 
type  of  fixture. 

Gauging.— Extensive  and  well-planned  ganging  is 
necessary  in  any  machine  shop  where  interchange- 
able  work  is  being  done.  There  is  a  constant  ten- 
dency  toward  degredation  of  quality  from  the  wear 
of  tools,  machines,  and  fixtures,  and  of  the  gauges 


FIXTURES  AND  GAUGES 


165 


themselves.  No  work  i«  ever  done  exactly  to  size. 
Precision  workmanship  simply  means  that  the  devia- 
tions are  known  to  be  very  minute. 

Three  terms  are  used  in  connection  with  these  dev- 
iations.   The  greatest  and  least  dimensions  above  and 
below  the  nominal  size  which  will  be  permitted  to 
pass  inspection   are   called   ** limits.''     These   limits 
have  been  determined  carefully  as  the  extremes  be- 
tween which  the  piece  is  sure  of  being  usable  for  the 
purpose  designed.     If  these  are  exceeded  the  work 
must  be  rejected.     The  difference  between  the  two 
limits  is  called  *' tolerance."    Deviation  from  the  nom- 
inal size  within  the  limits  is  unintentional,  but  per- 
missible.    *' Allowance''  is  an  intentional  difference 
in  size  of  two  parts  which  are  to  go  together.    If  the 
joint  is  to  be  a  drive  fit,  the  hole  is  purposely  made 
a  certain  amount  smaller  than  the  other  member.    If 
a  running  fit  is  desired,  it  is  purposely  made  a  cer- 
tain amount  larger.    It  is  evident  that  limits  may  be 
set  for  the  two  dimensions  called  for  by  the  allow- 
ance. 

Types  of  Gauges.— For  the  ordinary  gauging  of 
surfaces  and  angles,  it  is  customary  to  use  surface 
plates,  squares,  and  protractors.  For  very  accurate 
work  precision  methods  are  used,  which  will  not  be 
taken  up  here. 

For  linear  distances  the  simplest  form  of  gauge  is 
the  graduated  scale,  which  has  the  advantage  of  being 
available  for  any  length  within  its  limit  and  of  not 
wearing  out  in  use.  It  is  the  least  accurate  form 
of  gauge,  but  a  skilled  man  with  a  caliper  will  take 
off  dimensions  from  it  to  within  .002-.003  inch.    The 


I'tll 


166  THE  MECHANICAL  EQUIPMENT 

graduated  scale  constitutes  what  is  known  as  a  line 
measure,  where  the  eyesight  is  relied  on  in  determin- 
ing the  size,  and  because  of  its  convenience,  it  will 
always  have  a  place  where  great,  precision  is  not  re- 
quired.   Figure  32  shows  several  of  the  more  com- 
monly used  gauges.    End  measures,  as  they  are  called, 
comprise  bars   of   standard  length,   plug   and   ring 
gauges,  and  '*snap''  gauges.    When  these  are  used, 
the  work  is  gauged  by  thfe  sense  of  touch  and  not 
sight.    They  are  far  more  accurate  than  the  ordinary 
line  gauges,  but  in  generar  they  are  good  for  only 
one  size  and  are  subject  to  wear.    Differences  of  a 
few  ten-thousandths  of  an  inch  may  be  easily  detected. 
The  vernier  and  micrometer  types  of  calipers  com- 
bine the  advantages  of  both  line  and  end  measure 
svstems,  and  have  at  the  same  time  the  accuracy  of 
touch  of  an  end  measure  and  the  wide  range  of  sizes 
within  their  limits  characteristic  of  the  linear  scale. 
The  vernier  and  micrometer  calipers  were  both  intro- 
duced by  the  Brown  &  Sharpe  Manufacturing  Com- 
pany, the  vernier  in  1851  and  the  micrometer  in  1867. 
The  influence  of  these  two  types  of  gauges,  especially 
that  of  the  latter,  upon  the  standards  of  accuracy 
in  commercial  work  has  been  very  great,  for  they 
placed  in  the  hands  of  the  workman  convenient  and 
practical  tools  capable  of  measuring  differences  previ- 
ously unrecognized  in  practical  shop  work.    It  is  a 
well-defined  principle  that  the  limit  of  precision  in 
production  is  what  you  can  measure. 

The  linear  scale,  the  vernier,  and  the  micrometer 
are  used  mainly  in  the  tool  room.  For  general 
production  work,  plug  and  ring  gauges,  and  snap 


FIXTURES  AND  GAUGES 


167 


PLUG  AND  RING  GAUGES 


END  MEASURES 


LIMIT  SNAP  GAUGE 


LIMIT  PLUG  GAUGE 


DIAL   TEST  INDICATOR 


VERNIER    CALIPER 


MICROMETER  CALIPER 


yiG,    32,      TYPES    OP   GAUGES 


'Ml 


168  THE  MECHANICAL  EQUIPMENT 

gauges,  Figure  32,  are  more  used.  Any  of  these  may 
combine  two  sizes  and  become  a  limit  gauge.  These 
relieve  the  workman  in  the  shop  of  the  necessity  of 
exercising  judgment  in  determining  sizes  and  machme 
fits.  The  working  gauge  supplied  him  embodies  two 
dimensions  representing  the  limits  allowed,  the  differ- 
ence between  them  being  the  tolerance.  All  the  work- 
man has  to  do  is  to  make  sure  that  the  work  will 
pass  **A,"  and  will  not  pass  **B.''  The  limit  gauges 
shown  are  of  the  very  simplest  form.  For  special 
work,  they  are  varied  to  suit  the  special  case. 

Gauges  of  another  class— such  as  difference  gauges, 
dial  gauges,  and  indicators— are  used  by  tool  makers, 
not  so  much  to  determine  absolute  distances  as  to  as- 
certain differences  from  some  standard.    For  instance, 
the  diameter  of  a  shaft  would  be  measured  by  a  mi- 
crometer or  snap  gauge,  but  its  variation  in  alignment 
would  be  measured  by  an  indicator  or  dial  gauge  in 
thousandths  of  an  inch  without  reference  to  the  size. 
The  correctness  of  special  profiles  or  contours  given 
to  any  piece  of  work  is  determined  by  a  *' receiver'' 
gauge,  such  as  that  shown  in  Figure  33.    The  piece 
is  located  by  a  pin.  A,  which  fits  into  the  hole,  B. 
It  must  slide  on  to  the  pin.  A,  and  fit  accurately 
into  the  receiving  space,  C,  which  has  the  contour 
desired.    The  receiver  gauge  shown  is  also  provided 
with  a  snap  gauge,  D,  on  the  edge,  which  is  used  to 
gauge  the  thickness,  E,  of  the  piece.    The  one  shown 
is  very  simple  in  character.    When  the  surfaces  are 
irregular,  and  intricate  in  their  relationship  the  gauge 
may  become  a  delicate  and  complicated  affair. 
Another  class  of  gauges  is  used  for  locating  the  po- 


FIXTURES  AND  GAUGES 


169 


FIG.  33.   CONTOUR  GAUGE 

sition  of  pins,  holes,  and  surfaces.  Profile  or  receiver 
gauges  may  include  this  feature,  as  in  the  gauge 
shown  in  Figure  33,  which  locates  the  hole,  B,  with 
reference  to  the  contours  of  the  piece.  The  pin.  A, 
is  in  effect  a  plug  gauge  for  the  hole,  B.  The  more 
intricate  gauges  may  be  used  for  all  three  forms  of 
gauging— for  size,  contours,  and  location. 

General  Considerations.— In  shops  where  accurate 
work  is  done  in  great  quantities  there  will  be  three 
sets  of  similar  gauges:  wofking  gauges,  used  by  the 
workman  during  production;  inspector's  gauges,. used 
by  the  shop  inspectors,  and  master  gauges,  used  to 
check  the  other  gauges. 

The  working  and  inspector's  gauges  are  used  con- 
tinually and  are  therefore  subject  to  wear.  The  mas- 
ter gauges  remain  in  the  tool  room  and  are  used  for 
reference  only;  they  therefore  retain  their  size  a  long 
time. 

Gauging  is  done  at  various  stages  during  the  prog- 
ress of  the  work: 


a. 


First  piece  inspection— gauging  by  the  tool-setter  or  in- 


11 


M  7 
[  ■  I  , 

I'  > 


/(:• 


I- 


1 


I 


170  THE  MECHANICAL  EQUIPMENT 

spector,  to  insure  the  correct  setting  of  the  cutting 
tools  and  fixtures  before  proceeding  with  the  work. 

b  Working  inspection-gauging  by  the  workman  during  the 
progress  of  the  run,  to  discover  wear  of  cutting  tools, 
etc.,  or  changes  in  setting. 

c.  Operation  inspection-all  the  pieces  put  through  may  be 
gauged  by  an  inspector  before  proceeding  with  the  next 
operation.  This  is  done  to  detect  bad  woi:k  in  the  early 
stages  of  manufacture,  and  thereby  to  save  doing 
further  work  on  a  piece  already  spoiled. 

a.  Piece  inspection— by  the  inspectors,  of  the  finished  part 
before  it  is  sent  to  the  assembling  room. 

e.  Selective  inspection— This  is  often  practiced  when  the 
pieces  are  simple  and  made  in  very  great  quantities, 
such  as  hardened  balls  for  ball  bearings.  To  gauge 
each  one  would  add  greatly  to  the  cost  of  production. 
Only  one  out  of  a  certain  lot  or  number  is  gauged; 
if  this  passes  inspection,  the  rest  are  assumed  to  be 
correct ;  if  not,  others  are  gauged  and  if  a  certain  num- 
ber are  found  incorrect  the  whole  lot  i^  rejected. 

1  Unit-assembling  inspection— usually  done  in  the  assem- 
bling room,  to  make  sure  that  parts  of  certain  dehnite 
units,  as,  for  instance,  a  typewriter  carriage  or  a  lathe 
head,  are  in  proper  relation  to  one  another.  This 
may  involve  very  refined  types  of  position  gauges. 
g.  Performance  inspection— by  the  inspectors,  of  the  per- 
*  f  ormance  of  the  machine  as  a  whole. 

I  have  taken  up  the  work  of  the  tool  room  in  the 
foregoing  consideration  only  in  a  most  general  way, 
for  the  purpose  of  making  clearer  what  follows.  For 
detailed  consideration  of  tool-room  practice  and  the 
design  of  fixtures,  gauges,  and  special  tools,  the 
reader  is  referred  to  Dowd's  ** Tools  and  Patterns," 
Factory  Management  Course. 


II : 


CHAPTER  XII 
CUTTING  TOOLS 

MateriaI.~Since  the  purpose  of  all  the  machine 
tools  IS  to  drive  some  form  of  cutting  tool,  before 
taking  up  the  machines  I  shall  take  up  the  various 
forms  of  cutting  tools  used.  Cutting  tools  are  made 
from  tool  steel  or  from  some  form  of  abrasive.  The 
latter  material  forms  the  basis  of  grinding  wheels; 
while  their  action  is  that  of  pure  cutting,  they  con- 
stitute  a  distinct  type  of  tool  and  will  be  taken  up  in 
another  chapter. 

Carbon  Steel.— Formerly,  tool  steels  for  cutting  pur- 
poses were  composed  of  iron,  carbon,  and  minor 
elements  which  were  either  neutral  or  which  acted  as 
impurities.  These  steels,  known  as  carbon  steels, 
have  been  in  use  for  many  generations.  The  carbon 
content,  which  varies  from  0.80  to  1.50  per  cent,  gives 
the  steel  the  hardening  and  tempering  qualities  al- 
ready considered.  Good  carbon  steel  properly  heat- 
treated  is  as  hard  as  any  of  the  later  kinds  of  steel, 
and  in  fact  will  take  a  keener  cutting  edge.  Its  limi- 
tation, as  compared  with  high-speed  steel,  comes  from 
the  fact  that  it  begins  to  lose  its  hardness  when 
heated  above  400  degrees  Fahrenheit  and  conse- 
quently cannot  be  used  for  such  heavy  cuts  or  high- 
cutting  speeds.    For  finishing  work  and  for  light,  ac- 

171 


I 


172  THE  MECHANICAL  EQUIPMENT 

curate  cuts,  however,  carbon  steel  is  as  good  as  any 

''^wishet,  or  Self-Hardening  Steel.-This  kind  of  steel 
y^BiS  developed  between  1860  and  1870  by  Robert 
Mushet,  an  Englishman,  who  introduced  about  5.5 
per  cent  of  tungsten  and  1.6  per  cent  of  manganese 
into  the  steel,  which  caused  it  to  be  almost  as  hard 
when  cooled  slowly  in  the  air  from  a  forging  heat  as 
carbon  steel  when  quenched  in  water;  hence  the  name 
air-hardening,  or  self-hardening,  steel.  This  stee 
would  cut  faster  and  stand  more  abuse  than  any  steel 

then  known.  .  ,  -.tt  m 

High-Speed  Steels.— About  1900,  Frederick  W.  Tay- 
lor and  Maunsell  White  patented  a  steel  that  had  the 
quality  of  "red  hardness,"  so  called  because  it  would 
remain  hard  and  retain  a  cutting  edge  even  after  the 
ed<'e  was  red  hot.    A  cutting  tool  made  of  this  steel 
could  be  operated  on  cuts  so  heavy  and  fast  as  not 
only  to  turn  a  steel  chip  dark  blue,  but  even  to  rnake 
it  red  hot.    In  the  later  steels  described  by  Mr.  Tay- 
lor in  his  "On  the  Art  of  Cutting  Metals,"  the  tung- 
sten is  given  at  18.9  per  cent,  chromium  5.47  per  cent, 
carbon  0.67  per  cent,  and  manganese  0.11  per  cent.     He 
gives  the  following  cutting  speeds  for  these  various 
steels  when  cutting  machinery  steel: 


CUTTING  TOOLS 


Jessop  carbon  steel,  16  feet  per  minute 

Mushet  steel,  26  ^^ 

Original  Taylor- White  steel,  58 

Taylor- White  steel,  1906,  99 


(< 


Many  brands  of  high-speed  steel  are  noW  on  the 
market.    Compared  with  carbon  steel  it  is  very  expen- 


17J? 


fiive,  and  various  forms  of  tool-holders  have  be^n  de- 
vised to  economize  in  its  use.  Its  advantage  over 
carbon  steel  is  most  marked  in  the  making  of  heavy, 
rough  cuts,  work  in  which  the  purpose  is  to  remove 
as  much  material  as  possible  in  a  short  time. 

Mr.  Taylor's  paper,  *^0n  the  Art  of  Cutting 
Metals,''  read  before  the  American  Society  of  Me- 
chanical Engineers  in  1906,  is  one  of  the  greatest  con- 
tributions ever  made  to  machine-shop  practice.  In 
this  discussion  he  points  out  that  the  three  funda- 
mental questions  which  must  be  answered  every  day, 
in  every  machine  shop,  in  connection  with  metal- 
cutting  machines  such  as  the  lathe,  the  planer,  the 
drill  press,  the  milling  machine,  and  their  like,  are: 

1.  What  tool  shall  I  use? 

2.  What  cutting  speed  shall  I  use! 

3.  What  feed  shall  I  use? 

He  then  describes  experiments  which  covered  26  vears, 
employed  the  best  energies  of  a  number  of  experts, 
and  had  a  profound  effect  not  only  upon  cutting  steels 
but  upon  the  whole  design  of  machine  tools.  He 
shows  how  many  variables  were  involved  in  answer- 
ing the  three  questions  above,  and  the  principles  of 
successful  experimentation  in  working  out  a  prob- 
lem of  that  nature.  He  reviews  the  history  of  the 
investigation  with  the  successive  improvements  devel- 
oped, and  lays  down  standard  shapes  for  cutting  tools 
and  methods  and  formulas  for  determining  cutting 
speeds.  He  also  gives  a  full  description  of  the  com- 
position and  the  method  of  heat-treating  high-speed 
tool  steel.    While  the  paper  deals  mainly  with  heavy 


I 


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!  i 


I* 


174  THE  MECHANICAL  EQUIPMENT 

roughing  operations,  it  is  a  mine  of  general  informa- 
tion and  should  be  read  by  every  one  interested  in 
the  art  of  cutting  metals. 

A  wide  variety  of  cutting  tools  is  used  for  the  vari- 
ous types  of  operations  throughout  the  shop.  The 
principal  types  will  be  considered  briefly. 

The  Lathe-Planer.— This  type  of  tool  has  been  used 
for  a  hundred  years  or  more  and  is  the  typical  cut- 
ting tool  used  on  lathes,  boring  mills,  planers,  shapers, 
and  so  on.    It  has  a  single  cutting  edge,  shaped  to 
suit  the  particular  type  of  cut;  a  few  of  the  stand- 
ard forms  of  cutting  edge  are  shown  in  Figure  34. 
The  principal  ones  are  the  ** round  nose,"  A,  and 
diamond  point  tool,  B,  the  most  common  of  the  lathe 
tools.     These  remove  chips  easily,  and  are  used  for 
both  roughing   and  finishing   cuts.     Certain   angles 
have  generally  recognized  names.     The  angle,  a,  is 
called  the  top  rake;  b,  the  side  rake;  c,  the  clearance 
angle,  and  d,  the  angle  between  the  cutting  edges. 
C  and  D  are  right-  and  left-hand  side  tools;  E,  is  a 
parting,  or  cutting-off,  tool;  F,  is  a  bull-nose  tool; 
G,  a  finishing  tool.    There  are  some  minor  differences 
between  the  tools  used  on  lathes  and  on  planers  re- 
spectively, but  the  general  type  is  much  the  same  in 
both  cases.     Lathe  tools  should  be  set  so  that  the 
cutting  edge  is  slightly  above  the  center.    If  they  are 
set  so  that  it  is  below  the  center,  the  material  is 
scraped  off  instead  of  cut  off  and  the  cutting  edge 
is  soon  lost.     If  the  cutting  edge  is  too  far  above 
the  center,  the  pressure  comes  on  the  front  of  the 
tool,  and  not  on  the  cutting  edge.     On  many  planer 
tools  the  end  is  goose-necked,  as  shown  in  H,  Figure 


CUTTING  TOOLS 


FIG.    M.      TYPES   OF   LATHE   AND   PLANER   TOOLS 


34.  If  the  cutting  edge  is  forward  of  the  supporting 
surface  on  the  tool  head,  it  will  tend  to  dig  into  the 
material  when  taking  a  heavy  cut  or  upon  striking 
a  hard  spot  in  the  material.  If  the  cutting  edge  is 
even  with,  or  back  of,  the  supporting  face,  this  ten- 
dency is  done  away  with. 

The  advantages  of  the  lathe-planer  type  of  tool 
are  that  it  is  easily  sharpened,  and  can  be  used  for 
a  wide  variety  of  operations.     Its  disadvantage  lies 


'" .' 


V 


;1 


176  THE  MECHANICAL  EQUIPMENT 

in  the  fact  that  since  the  work  is  concentrated  on  a 
single  small  cutting  edge,  the  wear  is  rapid  and  the 
tool   must    be    frequently    re-ground.     With    carbon 
steels  the  shank  and  nose  of  the  tool  are  usually  a 
single  forging;  when  the  cutting  edge  has  worn  down 
beyond  a  certain  point,  the  tool  is  re-dressed  by  the 
blacksmith  and  used  over  again.     This  process  may 
be  repeated  until  the  shank  has  become  too  short 
to  be  used  in  the  tool-holder.    High-speed  steels  are 
too  expensive  to  be  used  in  this  way.     Figure  34 
shows  two  forms  of  tool-holders  in  which  the  shank, 
or  body,  is   a  machinery-steel   forging   carrying   at 
its  end  a  clamping  device  for  holding  a  small  bar 
of  high-speed  steel  which  can  be  moved  up  toward 
the  cutting  point  with  each  successive  grinding  and 
nearly  all  of  which  can  be  used. 

What  the  best  form  of  tool  will  be,  depends  on 
the  kind  and  hardness  of  metal  to  be  cut,  the  charac- 
ter of  the  cut— whether  roughing  or  finishing— and 
the  manner  of  presenting  the  tool  to  the  work.  Since 
a  tool  cuts  by  wedging  action,  the  sharper  the  cut- 
ting angle  the  less  power  it  takes  to  drive  it.  The 
cutting  angle,  d,  should  therefore  be  as  small  as  is 
consistent  with  strength.  In  general  the  angle  may 
be  more  acute  for  the  soft  metals  than  for  the  harder 
ones  such  as  chilled  cast  iron  or  tool  steel. 

The  surface  of  most  metals,  especially  that  of  cast- 
ings, is  harder  than  the  interior,  and  is  liable  to  con- 
tain some  sand  or  scale.  For  this  reason  a  first,  or 
roughing,  cut  should  be  deep  enough  to  go  beneath 
this  hard  surface;  otherwise  the  tool  will  be  quickly 
dulled.     For  roughing  cuts,  metal  can  be  removed 


CUTTING  TOOLS  177 

most  rapidly  by  taking  heavy  cuts  at  low  speed;  for 
finishing  cuts,  it  is  better  to  use  a  fine  feed  and  faster 
speed.     The  principal  limitations  of  feed  and  speed 
lie  within  the  tool  itself,  in  the  strength  of  the  tool, 
the  wear  of  the  cutting  edge,  and  the  heating  of  the 
tool  with  a  consequent  loss  of  hardness.    In  addition 
to  these  limitations  there  may  be  others,  from  lack 
of  stability  in  the  work,  which  may  be  too  weak  to 
stand  up  against  a  heavy  cut  and  spring  away  from 
the  tool;  or  the  lack  of  stability  may  lie  in  the  ma- 
chine tool  itself.     One  of  the  most  far-reaching  ef- 
fects of  Dr.  Taylor's  work  was  a  general  re-design  of 
machine  tools  to  furnish  the  power  and  stiffness  re- 
quired for  the  new  high-speed  steel  tools.    If  spring- 
ing is  bad  in  the  work  and  the  machine,  it  is,  of 
course,  equally  bad  in  the  tool  itself,  and  the  sup- 
porting point  of  the  tool  should  be  as  near  the  cutting 
edge  as  possible.    Cutting  speeds  vary  so  much  that 
only  a  general  idea  of  them  can  be  given  here.    For 
good  grades  of  carbon  steel,  such  as  Jessop's,  the 
approximate  cutting  speeds  are  as  follows: 

Fn^f  * ''p!!''- 30- 40  feet  per  minute 

i^or  wrought  iron 25—  30  " 

For  steel [['  i5__  ^q  «< 

^or  brass 60—100 

The  cutting  speed  is  of  course  affected  by  the 
amount  of  feed— a  higher  cutting  speed  is  possible 
with  a  light  feed  than  with  a  heavy  one. 

For  high-speed  steel  the  approximate  speeds  are  as 
tollows:* 


i|:  (« 


Modern  Shop  Practice,"  Vol.  I,  pp.  93-94. 


178 


THE  MECHANICAL  EQUIPMENT 


CUTTING  TOOLS 


179 


Soft  cast  iron 50—  60  feet  per  minute 

Hard  cast  iron 20—  40 

Hard  cast  steel 30—  40 

Soft  machine-steel 60—  90 

Hard  machine-steel 20 —  30 

Wrought  iron 35 —  45 

Tool  steel  annealed 50 —  80 

Tool  steel  not  annealed 15 —  20 

Soft  brass 110—130 

Hard  brass 90—110 

Bronze 60 —  80 

Gun  metal 40—  60 

A  general  idea  of  the  feeds  possible  can  be  gained 
from  the  following  table. 


5  per  inch 
5—8       " 


Roughing  cuts  on  cast  iron 

Roughing  cuts  on  machine  steel 

Sizing  cuts  on  cast  iron 12 — 16 

Sizing  cuts  on  machinery  steel 16 — 20 

Finishing  cuts  on  soft  cast  iron  with  a  narrow- 
point  tool 15 — ^25 

Finishing  cuts  on  machinery  steel  with  a  nar- 
row-point tool 20 — 40 

Finishing  cuts  on  cast  iron  with  wide-faced 
tool 1—4 

Finishing  cuts  on  machinery  steel  with  wide- 
faced  tool 4—8 

Finishing  cuts  for  brass,  according  to  kind  of 
cut  and  shape  of  tool 10 — 40 

The  above  speeds  and  feeds  are  for  tools  of  the 
lathe-planer  type. 

Multiple  Tool-Holders. — Tool-holders  may  be  ar- 
ranged to  carry  two  or  more  tools  of  the  lathe-planer 
type,  arranged  one  behind  the  other  with  reference 


<< 


i€ 


€t 


i« 


(C 


«« 


it 


to  the  direction  of  feed.  The  first  one  takes  a  rough- 
ing cut,  the  second  one  takes  up  the  cut  where  the 
first  one  leaves  off,  and  so  on  to  the  last  one,  which 
acts  as  a  finishing  tool.  This  is  done  for  heavy  work, 
and  is  found  more  frequently  on  heavy  lathes  and 
planers  than  elsewhere. 

Single-Edged  Forming  Tools.— When  the  finished 
surface  is  to  have  some  curve  or  other  definite  shape, 
this  shape  may  be  incorporated  in  the  cutting  edge 
of  the  tool.  Such  tools  are  known  as  forming  tools. 
They  may  be  either  flat  as  shown  at  A,  Figure  35,  or 
formed  bars,  as  at  B,  or  circular  as  at  C.  In  forms 
A  and  B  the  required  shape  is  given  to  the  front 
edge,  and  the  grinding  is  done  on  the  top.  In  form 
C  the  cutter  is  in  the  form  of  a  surface  of  revolution. 
Part  of  the  tool  is  cut  away,  leaving  a  cutting  edge 


^Shape  of 
surface  to  be 
formed 


TYPE- B 


Shape  of 
Surface 
to  be  formed 


VARIOUS  FORMED  CUTTING^ARS  FOR 
TYPE . B 


It'.  ♦ 


if.i  r 


B:i 


FIG.    35.      TYPES    OP    SINGLE-EDGED    FORMING    TOOLS 


180 


THE  MECHANICAL  EQUIPMENT 


It 


as  shown.  When  the  edge  becomes  dull  the  flat  face, 
c,  is  ground  away  as  much  as  may  be  necessary. 
This  process  may  be  carried  on  until  the  whole  cir- 
cumference of  the  tool  has  been  used. 

Milling  Cutters.— Figures  36  and  37  show  various 
forms  of  milling  cutters— used  on  milling  machines- 
profilers,  die-sinkers,  and  so  on.  In  these  a  number 
of  cutting  edges  are  arranged  around  the  circumfer- 
ence of  a  rotating  tool,  which  is  cylindrical,  or  some 
surface  of  revolution.  The  cutting  speed  comes  from 
the  revolution  of  the  cutter,  and  the  feed  is  usually 
given  by  moving  the  work  against  the  cutter,  al- 
though this  is  not  necessarily  so.  Although  they  are 
generally  considered  as  more  modern,  milling  cutters 
are  as  old  as  the  lathe  type  of  tool.  A  milling  cut- 
ter made  in  1780  by  Jacques  Vaucanson,  a  French  me- 
chanic, is  now  in  the  possession  of  The  Brown  & 
Sharpe  Manufacturing  Company.  This  cutter,  like 
most  of  the  early  milling  cutters,  has  very  fine  teeth. 
Modern  experiments,  however,  have  shown  that  mill- 
ing cutters  with  few  teeth  are  much  more  efficient. 

The  milling  cutter  has  a  wide  and  increasing  use. 
The  wear  is  not  concentrated  at  one  place,  as  in  a 
lathe  tool,  and  the  milling  cutter  will  therefore  hold 
its  shape  longer.  The  cutting  edge  of  the  lathe  tool 
is  in  the  work  during  the  entire  time  of  the  cut; 
with  the  milling  cutter,  any  single  cutting  edge  is  in 
the  work  only  a  small  proportion  of  its  revolution. 
Consequently  with  a  good  stream  lubrication  it  has 
time  to  cool,  which  means  that  the  cutting  speed  can 
be  higher.  While  the  cutting  done  by  any  given  edge 
is  intermittent,  the  cutting  is  continuous  so  far  as 


Wosher 


a-  PLAIN  MILLING  CUTTER 


e-  END  MILL  WITH  STRAIGHT  TEETH 


f-  END  MILL  WITH  SPIRAL  TEETH 


d- INTERLOCKED  SIDE 
MILLING  CUTTER 


g  -  T  SLOT  CUTTER 


b-  SIDE  MILLING  CUTTER 


C- SHELL  END  MILL  WITM 
SPIRAL  TEETH 


h- ANGULAR  CUTTERS 


f  •Jf 


■  •ITlr 


SHARPENED  WITHOUT  CHANGING 
CONTOUR 


MILLING  CUTTER  TYPE  OF  TEETH 


FIG.    36.      STANDARD    TYPES   OF   MILLING    CUTTERS 


I 


111 

!■!■ 


♦  I 


ii  11 


m 


Ha    37.      MILUNG    CUTTERS    WITH    OPPOSED    SPIRALS 

38X 


182 


THE  MECHANICAL  EQUIPMENT 


the  work  is  concerned.    There  is  therefore  a  saving 
in  time  over  a  planer  which  has  the  idle  return  stroke. 

Milling  cutters  are  made  in  an  infinite  variety  of 
forms.  The  plain  milling  cutter,  a,  Figure  36,  has 
teeth  on  the  circumference  only,  and  they  are  parallel 
to  the  axis.  When  the  teeth  are  parallel,  as  in  this 
type,  the  entire  cutting  edge  strikes  the  work  at  once, 
giving  a  tendency  to  produce  chatter,  which  increases 
with  the  width  of  the  cutter.  When  milling  cutters 
are  long,  the  teeth  are  arranged  spirally,  to  avoid 
end-thrust.  Two  cutters,  one  with  a  right-hand  spiral 
and  one  with  a  left-hand  spiral,  may  be  placed  side 
by  side,  as  shown  in  Figure  37.  The  side-thrusts 
then  will  neutralize  each  other.  Frequently  the  teeth 
are  nicked,  as  shown,  to  break  up  the  chips.  These 
nicks  do  not  appear  on  the  work,  since  they  are  stag- 
gered in  each  successive  tooth,  so  that  a  high  spot 
left  by  any  nick  is  cleared  away  by  the  tooth  follow- 
ing.  Cutters  made  in  this  manner  can  be  run  at 
coarser  feeds  than  those  with  plain  teeth. 

The  side  milling  cutter,  b,  Figure  36,  is  similar 
to  the  plain  one,  except  for  the  addition  of  teeth  on 
one  or  both  sides.  When  it  is  necessary  to  maintain 
accurately  the  distance  between  the  two  faces,  two 
such  cutters  are  placed  side  by  side  with  their  teeth 
**  interlocked  "—that  is,  with  the  alternate  teeth  on 
each  mill  reaching  over  into  the  zone  of  the  other 
cutter  (see  d.  Figure  36).  This  is  done  to  avoid  a  fin 
or  burr  on  the  work,  which  might  be  left  by  the  crack 
between  the  two  cutters.  The  width  between  the  side 
faces  is  maintained  by  packing  thin  washers  between 
the  cutters  each  time  the  teeth  are  ground. 


CUTTING  TOOLS  133 

A  face  milling  cutter  has  teeth  on  the  periphery 
and  on  one  face.     It  is  carried  on  the  end  of  the 
niachme  spindle,  the  teeth  on  the  flat  face  being  in 
full  contact  with  the  work,  while  only  a  small  length 
ot  the  teeth  on  the  periphery  acts  on  the  piece.    The 
shel   end  mill  is  similar  to  the  face  mill,  but  is  used 
for  light  operations.    It  may  be  solid,  with  a  taper 
shank,  or  separate,  as  shown  at  ^c."  End  mills  with 
right-hand  teeth  usually  have  a  left-hand  spiral  and 
vice  versa.    This  tends  to  force  the  shank  of  the  mill 
solidly  into  the  spindle  of  the  machine.    The  T-slot 
cutter,  g,  has  teeth  on  its  periphery  and  alternating 
teeth  on  the  side.    It  is  used  for  milling  T-slots  in 
fixtures  and  machine  tables.    Angular  cutters,  h,  have 
their  teeth  cut  at  some  oblique  angle.    They  are  em- 
ployed  for  finishing  dove-tails  and  on  a  wide  variety 
of  work  calhng  for  surfaces  machined  to  some  re- 
quired angle. 

Formed  cutters  (i  and  j)  are  an  important  class 
There  are  two  kinds  in  general  use.  In  the  first' 
the  teeth  are  of  the  same  character  as  those  of  plain 
milling  cutters  and  are  sharpened  by  grinding  on  the 
top  As  ordinarily  done,  this  changes  the  contour  of 
he  teeth  and  of  the  outline  produced  by  them,  which 
«  a  serious  objection  when  it  is  necessary  to  maintain 
the  original  form.     Special  machines  have  recently 

and  .f  r  ^^      !""  ''^''''^^^  this  type  of  cutter, 
and  at  the  same  time  preserving  the  original  contour 
ihe  other  style  of  cutter  has  teeth  that  are  -relieved  - 
f>nt  the  contour  is  retained  so  that  thev  may  be  sharn 
-ned  repeatedly  without  changing  the  original  form 
'^0  long  as  the  teeth  are  ground  radially  on  their  faces 


}>'••■! 


184  THE  MECHANICAL  EQUIPMENT 

With  this  style  of  cutter  interchangeable  work  of  a 
regular  outline  may  be  produced  more  cheaply  than 
by  any  other  method,  and  this  type  is  widely  used 
for  cutting  gear  teeth,  the  contour  of  the  cutter 
being  the  same  shape  as  the  space  between  the  gear 

teeth. 

The  fly  cutter  is  the  simplest  form  of  milling  cut- 
ter. A  tool  similar  to  the  lathe  type  which  may  have 
any  desired  form  of  cutting  edge  is  inserted  in  a 
holder  and  acts  in  the  same  way  as  one  of  the  cut- 
ting edges  in  an  ordinary  mill.  It  has,  of  course, 
only  one  cutting  edge,  but  it  can  be  made  at  little 
expense  and  is  used  for  short  operations  on  special 

work. 

When  milling  cutters  are  large,  the  cost  of  making 
them  entirely  of  tool  steel  would  be  very  high.  This 
cost  may  be  reduced  by  making  the  body  of  the  mill 
of  machine  steel  and  inserting  cutters  of  tool  steel. 
In  Figure  38,  **A'*  and  ''B''  show  cutters  of  this 
type,  and  ''C"  shows  one  of  the  methods  of  insert- 
ing the  teeth.  The  upper  screw  pulls  down  a  wedge 
which  forces  the  cutter  against  a  shoulder  integral 
with  the  body  of  the  mill.  Both  the  hole  in  the 
wedge  and  the  hole  in  the  body  of  the  mill  are  threaded. 
The  holding-down  screw  engages  the  threads  in  the 
body  of  the  mill,  but  does  not  engage  with  those  in 
the  wedge.  Its  action  is  therefore  to  draw  the  wedge 
downward.  When  it  is  necessary  to  remove  the 
wedge,  the  holding-down  screw  is  taken  out  and  a 
second  screw,  shown  below,  is  inserted.  The  action 
of  this  screw,  as  clearly  shown  by  the  figure,  is  such 
as  to  withdraw  the  wedge. 


CUTTING  TOOLS 


185 


B 


C  -  DETAIL  OF  METHOD  OF  SECURIMG 
CUTTERS  IN  A AND B 


TWO  TVP.S  or  .«c.  coTrc.Ps..yow,Ne  sr>H.,Ro  „,™oo  op 


FIG.   38.      TYPES  OP  INSERTED-TOOTH   MILUNG   CUTTERS 

Gang  Mills.— These  receive  their  name  from  the 
tact  that  two  or  more  cutters  are  placed  together  on 
tlie  same  arbor  and  are  used  at  the  same  time.  (See 
Figure  39.)  "Sometimes  plain  milling  cutters  are  so 
combined  in  order  to  cover  a  wider  space;  and  again, 
termed  cutters  may  be  used  either  with  or  without 
plain  or  side  milling  cutters.  The  use  of  formed  cut- 
ters and  plain  milling  cutters  together  should  be 
avoided  on  account  of  the  difficulty  of  maintaining 
the  relative  diameters  in  sharpening.  .  .  .  Gang 
milling  reduces  the  cost  of  production  and  insures 


186 


THE  MEl  HANICAL  EQl  II\MENT 


FIG.    39.      HEAVY    GANG    MILLING    CUTTER 


accuracy  of  work,  as  several  operations  can  be  per- 
formed simultaneously  and  at  one  setting."* 

In  milling  of  this  kind  the  cutters  of  the  largest 
diameter,  which  of  course  have  the  heaviest  work  to 
do,  should  if  possible  be  nearest  the  spindle,  and  it 
is  often  desirable  to  have  some  of  the  cutters  right- 
hand  and  some  left-hand  spirals  in  order  to  equalize 
the  end-thrust.  Sometimes,  when  the  cutters  vary 
considerably  in  diameter,  the  inequality  of  the  peri- 
pheral speeds  may  be  cared  for  by  having  the  large 
cutters  made  of  high-speed  steel  and  the  smaller  ones 
of  carbon  steel. 


♦  "Treatise  on  Milling  Machines,"  Brown  &  Shnrpe  Mfg.  Co. 


CUTTINO  TOOLS  137 

Speeds  and  Feeds.-  -The  speeds  and  feeds  in  mill- 

itToTirr;  ''\''^r^^'  -  the  power  an^  nS- 

andln  h    f  T'  T^^"'''  ^^^^  ^^  ^^terial,  width 
and  depth  of  cut,  and  quality  of  finish  required     No 
dehmte  rules  are  established.    Delicate  work  requir 
mg  accurate  finish  calls  for  light  cuts  and  fine  feed 
In  general,  the  speed  should  be  as  fast  as  the  cutter 
wi  1  stand,  and  the  feed  as  coarse  a^  is  crnsSent 
with  good  work.     The  following  surface  speed     13 
voeated  by  Brown  &  Sharpe  in  their  treatise  on^'Mnt 

„.„  SPEED  IN  FEET 

CARBON  STEEL  CUTTERS        prr  miNUTE 

Z,^^^ SOtolOO 

J;"«V        40to   60 

Machinery  Steel goto   40 

Annealed  Tool  Steel 20  to  30 

SPEED  IN  FEET 
HIGH-SPEED  STEEL  CUTTERS     PER  MINUTE 

^^f; • 150to200 

5^'*>» SOtolOO 

Machmery  Steel gotoioo 

Annealed  Tool  Steel. 60  to  80 

Drills._DriIls   are  used   for   originating  holes  in 

ht  elf  •  1  ^  f'i"  ™*^*^^'  ^"^  -«  P--<ie5  -""-t 

ZeforTf       '"^  "'  "'  P"'"*-    ^*  ^^  distinguished, 
therefore    froni  a  reamer,  which  has  cutting  edges 

fat  dri,r  r-    """"f  '''  ''  *"«  ^^"^'•«'  classel    The 
«a  dnil,  shown  at  "A,"  Figure  40,  is  the  oldest  type 

but  IS  comparatively  little  used  today.  ^^' 

ihe  prevailing  type  of  drill  is  the  twist  drill,  shown 


isi; 


TllK   .MKCIIANICAL   Ki^ll  PM  KNT 


FIG.    39.       HEAVY    <1AN(1    MILLIN(J     CTTTER 

aeeuraey  of  work,  as  several  operations  caii  U^  per 
formed  simultaneously  and  at  one  setting-."* 

In  niillino-  of  this  kind  the  cutters  of  the  largest 
diameter,  which  of  course  have  the  heaviest  work  to 
do,  should  if  possihle  be  nearest  the  spindle,  and  il 
is  often  desirable  to  have  some  of  the  cutters  right 
hand  and  some  left-hand  spirals  in  order  to  equalize 
the  end-thrust.  Sometimes,  when  the  cutters  varv 
considerably  in  diameter,  the  inequality  of  the  pen 
pheral  speeds  may  be  cared  for  by  having  the  laigv 
cutters  made  of  high-speed  steel  and  the  smaller  on'^^ 
of  carbon  steel. 


*  "Tmitise  on  Millinjr  Ma<'hiiu>s."  Rn.wn  i^  Sluiip*'  Mfj:.  Co. 


CllTVlsa  TOOLS  187 

Speeds  and  Feeds.-  -The  sp.eds  and  feeds  in  mill- 
^  jerations  ar.  dependent  or,  the  power  and  rigid- 
't>  0    the  diNerent  machines,  kind  of  material,  width 
-;'  ^i;Pth  of  cut,  and  quality  of  finish  required     lo 
:'^*<^'^^te  rules  are  established.     Delicate  work  requh-! 
n.g  accurate  finish  calls  ior  light  cuts  and  fine  ?^ed 
in  genera  ,  the  speed  should  be  as  fast  as  the  cutter 
w.      stand,  and  the  feed  as  coarse  as  is  conJ^n 
^Mtli  good  work.     The  following  surface  speed      'd 
->-^ted   ,y  Brown  &  8harpe  in  their  treatise  oi'\li" 
ing   Machines,'^   will    oiye   som^   ;.^.       / 
practice:  "         ^"''   ^^'^^   "^    prevailing 

SPEED  rx  FEET 
f-ARBON   -,TKKI,    CfTTKRS  PFR  MINUTE 

f:'''\ HOtolOO 

^fV"" -*0to    60 

Miicliiiipiy  Stool 3Q^^   ^Q 

Aniioalcd  Tool  Steel :>o  to   .'50 

SPKED  IN  FEET 

ri„;H.RPrF:n  stkri,  c-ttkrs        pkr  minute 
!:'"":'% 150  to  200 

[r{     SOtolOO 

.Mm-hniory  Steel gOtolOO 

Aniioiileil  Tool  Steel eo  to   80 

-Ko;:;:^'"\"',  T   T^    <■"'•    originating,    holo.   h 

I  s  oek     A  dnll  rotate..,  and  is  provided  with  ent- 

'I'lff  edges  located  at  its  noinf      Tf  ;.    r  ♦•  ,     , 

Iherefnr...     t  '^  "   '•    <'''*t]ngiiislio(  . 

'  efore    froni   a  reamer,  which   has  cutting  edges 

to  sides.    Dnils  are  of  two  general  classed.     The 

'nil,  shown  at  "A,"  Figure  40,  is  the  oldest  tvpe 
'•''IS  comparatively  little  „sed  today.  '  ^  ' 

iUe  prevailing  type  of  drill  is  the  twist  drill,  shown 


i 


188 


THE  MECHANICAL  EQUIPMENT 


a-  FLAT   DRILL 


b-  TAPER  SHANK  STRAIGHT  FLUTED  DRILLi 


C  -  STRA16HT  SHANK  Sr«AI6HT  FLUTED  DRILL 


d-  5TRAI6HT  SHANK    TWrST  DRILL 


e-TAPEH    SHANK  TWIST    DRILL 


■il2%/i': 


f-  STANDARD  ANOLES  ON  A  TWIST  DRILL 


q-  END  OF  A  SINGLE 
LIPPED  DEEP  HOLE 
DRILL 


WG.   40.      TYPES   OF   DRILLS 


CUTTING  TOOLS  139 

at /'D''  and  "E,"  Figure  40.    This  usually  has  two 
spiral  flutes,  which  are  sharpened  on  the  end,  and  are 
ground  down  as  the  tool  wears.     Twist  drills  are 
made  m  all  sizes,  for  the  smallest  hole  up  to  about 
tour  inches  in  diameter,  although  they  are  not  common 
much  above  two  inches  diameter.     They  may  have 
straight  shanks,  or  tapered  shanks  made  to  one  of  the 
well-known  standards  prevailing,  such  as  the  Morse 
taper,  which  is  %  inch  to  the  foot.     This  type  of 
drill  was  developed  about  1860,  and  has  marked  a 
very  important  advance  in  mechanical  history     There 
are  many  refinements  in  the  design  and  manufacture 
of  these  drills  which  cannot  be  taken  up  here.    The 
point  of  the  drill,  F,  Figure  40,  is  ground  off  at 
an  angle  of  59  degrees  with  the  axis.    The  ends  are 
not  truly  conical  but  are  slightly  spiral  to  give  re- 
0  .    ,i  /""'°^  ^^^^'  *^^  ^"^'«  »f  clearance  being 

Z  /  .».  '^f -n  •  ^*  ^'  ""^"^  ^^«^"«al  tJiat  the  two 
ips  of  the  drill  should  be  absolutely  symmetrical, 
that  IS,  the  cutting  edges  at  equal  angles  and  of 
equal  length;  otherwise  the  pressure  will  be  heavier 
on  one  side  than  on  the  other,  and  the  drill  will  run 

itself"  ^  ^°'^  ^^"^^'' '°  *^^^™^te^  tlian  the  drill 

The  speeds  of  drills  must  be  varied  to  suit  the 

mended  by  the  manufacturers  of  twist  drills  for  soe- 
cial  cases  The  following  recommendations  are  made 
by  the  Cleveland  Twist  Drill  Company: 

^u'bon  sttl  Ss  with  r  n/"^  '■  ''  ^  ^'^  ™'«  t°  «tart 
Bieei  urilis  with  a  peripheral  speed  of  30  feet  per 


If    I 


i 


190 


THE  MECHANICAL  EQUIPMENT 


minute  for  soft  tool  steel  and  machinery  steel ;  35  feet  for  cast 
iron,  and  60  feet  for  brass ;  and  a  feed  of  from  .004  to  .007 
inch  per  revolution  for  drills  one-half  inch  and  smaller,  and 
from  .005  to  .015  inch  per  revolution  for  drills  larger  than 
one-half  inch.  At  these  speeds  and  feeds  a  good  cutting 
compound  is  recommended.  In  case  of  high-speed  drills  the 
above  feeds  should  remain  unchanged,  but  the  speeds  should 
be  increased  to  from  2  to  21/2  times. 

The  cutting  compound  referred  to  is  mainly  for  the 
purpose  of  cooling  the  tool.  The  following  com- 
pounds are  recommended  in  the  order  named: 

For  hard,   refractory  steel — ^turpentine,   kerosene,   or  soda 

water. 
For  soft  steel  and  wrought  iron — ^lard  oil  or  soda  water. 
For  malleable  iron — soda  water. 
For  brass — a  flood  of  paraffine  oil,  if  any. 
For  aluminum  and  soft  alloys — ^kerosene  or  soda  water. 
Cast  iron  should  be  worked  dry  or  with  a  jet  of  compressed 

air. 

Special  forms  of  drills  are  used  for  many  purposes. 
For  drilling  soft  metal,  such  as  brass,  especially  when 
the  drill  passes  entirely  through  the  piece,  straight 
fluted  drills  of  the  type  shown  at  C,  Figure  40,  are 
used.  For  deep-hole  drilling,  such  as  rifle  barrels 
in  hard  stock,  a  special  form  shown  at  6,  Figure 
40,  which  has  a  single  cutting  edge,  a,  and  a  passage, 
b,  for  the  cutting  lubricant,  which  is  fed  under  pres- 
sure, has  been  developed. 

In  general,  the  drill  is  not  a  very  accurate  tool. 
There  is  a  heavy  pressure  on  the  conical  point,  which 
tends  to  press  the  tool  off  to  one  side  if  the  con- 
ditions at  the  point  are  not  exactly  right.  The  sur- 
prise is  not  so  much  that  they  are  inaccurate  as  that 


CUTTING  TOOLS  igj 

they  do  their  work  as  well  as  they  do.    When  verv 

str!ShTcu^^^^    r''"'^^  ^^^^^^  i«  ^  '^ol  with  long, 
iS^Fi^^^^^^  with  its  axif: 

is  ua«i  vh™  L    >»»Je«M  to  the  greatest  wear.    Oil 

<«  set.i„ ... .,.  i;:i  ^it^j-'t, Tr 
....» iLr:  r„rti,nat;/'s '° '°  -: 

accuracy  of  work  '  ^^  ^creased 

^'■i. ....  J  thX't  z  ttr„r  tS'e  te"r„ 


I 


I 


STANDARD  HA.ND  REAMER 


EXPANSION    REAMER 


STANDARD  SHELL  REAMER 


ROUGHING  AND  FINISHING 

MORSE  TAPER  REAMER 

WITH  SQUARE  SHANKS 


STANDARD  ROSE  SHELL  REAMER 


SOLID  ADJUSTABLE  BLADE  SHELL  REAMER       SECTION  SHOWING  CONSTRUCTION 
WITH  CARBON  OR    HIGHSPEED  OF  ADJUSTABLE  BLADE  REAMERS 

STEEL  BLADES 


FIG.  41.     TYPES  OP  REAMERS 


192 


CUTTING  TOOLS 


193 


FIG.   42.      TAPS 

Mo.f  nV.1.    ^P'ndle,  so  that  the  tap  is  free  to  fall 


11  V 

m 


194 


THE  MECHANICAL  EQUIPMENT 


but  there  are  other  well-established  forms  that  are 
used  for  special  purposes.  The  desirability  of  uni- 
formity in  screw  threads  is  so  great  that  the  stand- 
ard should  not  be  departed  from  except  for  very 
good  reasons.  The  detailed  consideration  of  the  vari- 
ous standard  forms  of  threads,  and  their  uses,  will 
be  given  in  the  chapter  on  Thread  Cutting. 

There  is  a  wide  variety  of  taps  for  special  pur- 
poses. The  first  one  shown.  A,  Figure  42,  is  known 
as  the  tapered  tap.  It  will  be  noted  that  the  whole 
of  the  thread  is  cut  away  on  the  front  end,  the 
amount  gradually  lessening  until  full  threads  are  left 
in  the  upper  part  of  the  tap.  This  distributes  the 
work  of  cutting  along  the  length  of  the  tap,  and  con- 
sequently relieves  the  wear  on  the  threads.  The 
final  threads  have  little  to  do  except  to  bring  the 
work  to  exact  size.  This  type  of  tap  is  used  in  holes 
that  go  clear  through  the  work.  The  second,  or  plug, 
tap,  B,  is  used  for  threading  holes  that  do  not  go 
through,  but  where  a  few  imperfect  threads  at  the 
bottom  of  the  hole  are  not  objectionable.  The  bot- 
toming tap,  C,  is  used  when  it  is  necessary  to  cut 
the  threads  quite  to  the  bottom  of  the  whole.  This 
form  is  not  used  except  when  absolutely  necessary. 
As  will  be  seen,  the  plug  tap  is  a  compromise  be- 
tween A  and  C. 

Taps  are  also  made  with  long  shanks  when  threads 
are  required  at  the  bottom  of  a  long  hole.  As  the 
size  of  the  tap  increases,  a  point  is  reached  where 
inserted  tooth  cutters  become  profitable,  as  in  the 
case  of  milling  cutters  and  reamers.  This  also  al- 
lows for  adjustability   in   connection   with   regrind- 


CUTTING  TOOLS  195 

Wk  J^^.1'  ^'^\^^^^^  cutting  tools,  must  have  relief 
back  of  the  cutting  edge,  and  in  most  of  the  solid 
taps  now  used,  when  they  are  reground  on  the  face 
there  is  a  sLght  change  in  size.  When  the  taps  are 
arge  enough,  this  may  be  compensated  for  hjlZ. 
ting  the  tap  and  spreading  the  sections  apart  w  h 
a  threaded  taper  plug  which  acts  along  the  aLil  of 
the  tap,  as  shown  in  D,  Figure  42. 

Dies.--Taps  are  used  for  cutting  internal  threads- 
externa  threads  are  cut  in  dies.  Figure  Shor^^^^^ 
simplest  form  of  solid  threading  die  Dies  as  well  as 
taps  must  have  a  relief  back  of  the  cutting  edge  as 
they  also  will  lose  their  size  on  regrinding^  ^^^^^^ 
may  be  compensated  for  by  slitting  the  die  and 
springing  It  together  with  an  adjusting  screw  in  the 

PoSs  anT'".".?^'  ^^  *^  «P^^*  *^'  ^-  -toM': 
portions  and  make  these  adjustable  in  the  die-holder 

toward  each  other.    For  large  work  and  for  accumte 

Puichei  %^''T^'^  ^^t^r  "«der  Screw-Threading 
Funches.-Punches  are  used  for  originating  holes 


SOLID 
THRCAOING  Dies 


^  ADJUSTABLE 
THREADING  DIES 


WG.   43.      THREADING  DIES 


'    ' 


ht'fl'; 


IIG.  44     PUNCH 


r> 


196  THE  MECHANICAL  EQUIPMENT 

in  thin  stock  when  accuracy  is  not  required.     They 
are  usually  round,  but  there  is  no  reason  why  an 
odd-shaped  hole  may  not  be  punched  as  well.     The 
simplest  form  of  punch  is  a  short,  cylindrical  tool  with 
a  flat  end  which  goes  through  a  corresponding  ring 
known  as  the  die.     The  material  is  placed  between 
the  two,  and  the  punch  forces  a  plug,  or  wad,  the 
size  of  its  own  diameter  through  the  hole  in  the  die. 
The  die  is  always  fixed  to  the  bed  of  the  machine, 
and  the  punch  is  carried  on  a  movable  power-driven 
head.    The  work  of  punching  with  a  punch  that  has  a 
flat  end  is  very  severe,  since  all  of  the  circumference 
begins  to  cut  at  once.    A  punch  with  a  curved  edge  of 
the  type  shown  in  Figure  44,  relieves  the  suddenness 
of  this  shock.    In  this  type  the  conical  point  in  the 
middle  enters  the  plate  first,  and  holds  it  securely. 
The  lower  portion  of  the  curved  edge  enters  the  work 
first,  and  the  highest  portion  is  last.    This  distributes 
the  work  of  cutting  through  a  vertical  zone  repre- 
sented by  the  difference  in  height  of  the  lowest  and 
highest  portions  of  the  edge.    A  punch  does  not  have 
to  cut  its  way  entirely  through  the  plate,  as  the  plug, 
or  wad,  is  sheared  completely  from  the  surrounding 
material  after  the  punch  has  gone  part  way  through, 
and  from  then  on  the  punch  has  merely  to  push  the 
plug  out.    The  percentage  of  the  work  actually  per- 
formed to  the  apparent  work  of  cutting  the  entire 
thickness  of  plate  is  lowest  for  thick  plates,  varying 
from  about  25  per  cent  on  a  one-inch  plate,  and  37 
per  cent  for  a  half-inch  plate,  to  about  75  per  cent 
for  a  plate  1/16  inch  thick.    For  very  thin  plates,  it 
approaches  100  per  cent.    In  large  machines,  a  num- 


CUTTING  TOOLS  197 

\Z  If  fr"!!"'  ""^^  ^'  ^P"'^*"^  "^  ^^gangs.-  Punch- 
i  in  \  ?^f  S^'^^  ^^'*  '^^'^  ^^y  ^f  producing 
S  ro'.fr'  ''^^'-  I'  ''^  ^^— ^  -  --curat? 
TI  .^  ''''^'''  ^""^  ^h^n  accurate  work  is  re- 
quired the  holes  should  be  drilled 

fnr  .T*""?'^"''  ^'  ^^'''  ^^^^  ™Plies,  are  used 
to  suit  the  material.     For  cutting  plates    straight 

tfnfedt"t^'^^'" '-'  "^^^^^-  ^'-'  wfhrt 

t  ng  edge  set  at  an  angle  to  distribute  the  work  of 
eutxng  and  to  relieve  the  machine  from  the  shock 

TonTe        ""''  ''  '''  '''''''  ^^^^  -^-^^  the  work 

sto!r*Th?r  t'  ^^''  T^  ^''  ^^*«^^  ^P  rough 
Ted  for  .H^^^^'  ^""^-'^^  ^^'  it«  counterpart, 

with  1\'S',^"'  f  '"^'  ''''''  ^'^^^  '^  '^'^  -ide' 
^itn  a  hole  in  each  end.     This  is  mounted  in  thp 

frame  of  an  automatic  machine  which  giv^the^^^^^^^^^ 

or  metll    flT""  ''"t.    ^""^^^^  «^"«  ^^^  -^  used 
lor  metal-they  generally  consist  of  a  soft  steel  di^k 

S  'ZTiT'^'  "TT'  •-"■■  ■f--  St 

acK  saws,  do  their  work  by  pure  cultins  action 
l»m  disk  of  soft  stee]  which  runs  at  very  m-eal  ™ri 

ot  work  to  be  cut  is  concentrated  at  the  point 


f'  ! 


198  THE  MECHANICAL  EQUIPMENT 

of  contact;  on  the  saw  it  is  distributed  around  the 
entire  circumference,  and  the  cooling  stream  is  suf- 
ficient to  preclude  heating.  The  disk  therefore  liter- 
ally melts  its  way  through  the  work  with  a  rapidity 
incredible  to  those  who  have  not  seen  it  work.  This 
type  of  saw  may  be  used  to  cut  hardened  tool  steel. 
In  this  case  the  temper  will  be  drawn  for  a  slight 
distance  possibly  1/64  or  1/32  inch  back  from  the 
surface.  This  may  be  ground  off  on  an  emery  wheel 
down  to  the  hard  metal  and  the  piece,  if  it  is  a  cut- 
ting  tool  such  as  a  threading  die,  will  be  again  ready 

for    ^^^'  .  XI  I.-    u 

There  are  many  special  forms  of  cutting  tools  which 
do  not  fall  under  any  of  the  classes  described.  Some 
of  these,  such  as  broaches,  hobs  and  forming  tools 
for  stampings,  will  be  taken  up  in  connection  with 
the  machine  tools  with  which  they  are  used. 

Cutting  Lubricants.— A  list  of  the  cutting  lubri- 
cants suggested  by  one  of  the  well-known  firms  was 
given  in  connection  with  twist  drills.  In  most  of 
the  machining  operations  some  form  of  lubricant  is 
used,  the  conspicuous  exceptions  being  the  cutting  of 
cast  iron  and  brass,  which  is  done  dry.  In  general, 
lard  oil  is  an  excellent  lubricant  when  turning  or 
threading  steel  or  wrought  iron,  and  it  is  largely  used 
on  automatic  screw  machines,  especially  on  small 
work.  For  high  cutting  speeds,  soda  water  is  more 
satisfactory,  as  oil  is  more  sluggish  and  does  not 
reach  the  cutting  point  with  sufficient  rapidity. '  Many 
cutting  compounds  are  on  the  market  which  consist 
usuallv  of  a  mixture  of  carbonate  of  soda  and  water, 
with  iard  oil  or  soft  soap  to  thicken  it,  and  which 


CUTTING  TOOLS 


199 


act  as  a  lubricant.    The  different  kinds  of  lubricants 
for  the  various  types  of  cuts  on  the  various  metals 
are  so  many  that  they  cannot  be  taken  up  here.  Fred- 
erick W.  Taylor  was  the  first  to  point  out  the  great 
saving  in  stream  lubrication  for  a  cutting  tool.    One 
of  the  principal  limitations  to  the  cutting  speed  is 
the  rise  in  temperature  of  the  tool,  with  the  conse- 
quent drawing  of  the  temper  and  loss  of  cutting  edge. 
He  discovered  that  a  heavy  stream  of  water-— not  the 
little  dribble  previously  used,  but  a  heavy  stream 
poured  directly  on  the  chip  at  the  point  where  it 
was  being  removed  by  the  tool— would  permit  an  in- 
crease in  cutting  speed  amounting  in  some  cases  to 
30  or  40  per  cent.    The  stream  is  used,  not  for  lubri- 
cation, but  for  the  purpose  of  carrying  away  the  heat 
generated  at  the  point  of  the  tool.    This  practice  has 
become  very  general  for  heavy  roughing  cuts  of  the 
kind  described  by  Dr.  Taylor. 


CHAPTER  XIII 


LATHES 


LATHES 


201 


Development  of  the  Lathe. — The  lathe  is  the  oldest 
of  the  machine  tools.  In  its  rudimentary  form — as, 
for  instance,  the  potter's  wheel — it  comes  down  from 
the  earliest  dawn  of  civilization.  In  the  old  whip 
lathe  the  work  was  mounted  on  two  centers.  A  cord 
was  run  from  a  long  wooden  spring,  secured  to  the 
ceiling,  down  to  the  work,  around  it  for  one  or  two 
turns,  and  then  on  down  to  a  foot  treadle  on  the 
floor.  By  the  working  of  the  foot  treadle  the  piece 
to  be  cut  was  oscillated  backward  and  forward,  and 
a  hand  tool,  resting  on  a  guide  in  front  of  the  work, 
was  used  to  do  the  cutting.  The  cut  was  taken  with 
every  alternate  movement  as  the  work  rotated  for- 
ward. Later,  the  continuous  revolution  was  substi- 
tuted for  oscillating  motion,  but  the  driving  cord  was 
still  carried  around  the  piece  itself.  In  the  next  step 
in  the  development,  the  work  was  mounted  on  cen- 
ters as  before,  but  was  connected  by  suitable  means 
to  a  live  spindle  which  had  a  permanent  pulley  driven 
by  the  belt.  With  all  of  these  types  only  hand  cut 
ting  tools  were  used.  It  is  rather  surprising,  as  we 
look  back,  to  see  what  good  turning  was  done  in  this 
way  at  such  an  early  period  of  mechanical  develop- 
ment. 

200 


Henry  Maudslay  and  Modem  Tools. — Modern  tools 
really  had  their  beginning  with  the  application  of  the 
** slide  rest"  principle  to  turning  lathes  by  Henry 
Maudslay,  a  principle  which  has  been  extended  to 
nearly  every  form  of  machine  tool.  It  was  first  de- 
veloped by  Maudslay  between  1790  and  1800  in  the 
shop  of  Joseph  Bramah,  in  London.  Instead  of  being 
manipulated  by  hand,  the  cutting  tool  was  clamped 
solidly  in  a  tool  post  carried  on  a  slide  rest  movable 
along  accurately  finished  guides  on  the  bed  of  the 
machine.  For  many  years  the  slide  rest  was  known 
in  English  as  **  Maudslay 's  Go-Cart.'' 

In  its  first  and  simplest  form  the  motion  was  con- 
trolled by  hand-operated  screws.  In  a  short  time, 
provison  was  made  for  connecting  the  operating 
screws  by  gearing  to  the  driving  spindle,  giving  the 
tool  a  power  feed.  This  invention  enormously  in- 
creased the  accuracy  of  the  machine  as  well  as  the 
size  of  the  cuts  which  could  be  taken.  The  old  hand 
tools  had  to  be  skillfully  used,  for  occasionally  they 
**dug  in"  and  lifted  the  workman  over  the  lathe. 

The  lead  screw,  for  which,  also,  Maudslay  is  respon- 
sible, followed  within  a  very  few  years,  and  was  a 
natural  development  from  the  slide  rest.  In  its  first 
form,  Figure  45,  a  lead  screw  with  the  same  number 
of  threads  per  inch  as  it  was  desired  to  cut,  was 
attached  to  a  slide  rest  and  driven  at  the  same  speed 
as  the  work.  This  caused  the  cutting  tool  in  the 
slide  rest  to  move  forward  over  the  work  and  generate 
the  screw  thread  required.  It,  of  course,  necessitated 
a  separate  lead  screw  for  every  pitch  to  be  cut. 
Within  a  year  or  so  Maudslay  developed  the  idea 


SJ.'!; 


y] 


I 


■"i 


I 


202 


THE  MECHANICAL  EQUIPMENT 


FIG.  45.    maudslay's  first  screw-cutting  lathe, 

ABOUT    1797 

of  a  single  lead  screw,  much  more  accurately  formed, 
which  could  be  made  to  cut  any  pitch  of  thread  by 
changing  its  turning  velocity,  relatively  to  the  work, 
through  a  gear  reduction.  The  various  gears  used 
to  change  the  speed  of  the  lead  screw  are  still  known 
as  ** change  gears." 

These  essential  features  of  the  screw-cutting  lathe, 
although  varied  in  proportions  and  greatly  improved 
in  workmanship,  remain  unchanged  in  principle  to 
this  day.  Maudslay  lived  until  1830;  shortly  before 
his  death  he  built  a  lathe  capable  of  turning  work  12 
feet  in  diameter  and  boring  steam  cylinders  up  to  ten 
feet  in  diameter,  which  shows  the  remarkable  devel- 
opment in  this  machine  during  the  lifetime  of  one 
man.  So  important  were  Maudslay 's  contributions 
that  he  may  well  be  termed  the  father  of  modern 
machine  tools.  The  back  gears  used  to  increase  the 
power  of  the  drive  were  invented  by  Richard  Roberts 
about  1817.    From  1830  onward  there  was  little  dv- 


LATHES 


203 


FIG.   46.      SPEED    LATHE 
Oliver  Machinery  Co. 

velopnient  in  the  essential  design  of  the  turning  lathe 
until,  about  25  years  later,  the  turret  lathe  was  de- 
veloped, and  later  still  the  automatic  turret  lathe. 
Both  of  these  are  American  in  their  origin. 

The  Speed  Lathe.— The  simplest  form  of  lathe  used 
today  is  the  speed  lathe,  Figure  46,  which  consists 
of  a  bed  having  guides  or  ways  on  its  top,  and  at 
one  end— invariably  the  left-hand  end  as  the  workmen 
faces  the  machine— a  headstock,  or  casting,  contain- 
ing two  bearings.    In  these  bearings  is  the  live  spin- 


h 


202 


THE  MKCHAMCAL   KQril\\IKi\1 


FIG.  45.    maudslay's  first  screw-cutting  lathe, 

ABorT  171)7 

of  a  siniilc  lead  screw,  niiich  more  accurately  roinicd, 

which  coiihl  ho  made  to  cut  any  pitcli  of  tlircad  by 

c]ian<»ini^  its  turnin^;-  vok)city,  ridativcly  to  the  work, 

tlirougli   a  n'ear   reduction.     Tlie   various   iACjirs    used 

to  chaui^e  the  speed  of  the  h^ad  screw  are  still  known 

as  *' change  gears." 

Tliese  essential  features  of  the  screw-cutting  lathe, 

althougli  varied  in  proportions  and  greatly  improved 

in    workmanship,    remain    unchanged    in    piinciple   to 

this  ilay.     ^laudslav  lived  until  18o();  shortly   het'ore 

his  death  he  huilt  a  lathe  ca})ahle  of  turning  work  ll' 

feet  in  diameter  and  horing  steam  cylinders  up  to  ten 

feet  in  diameter,  which  shows  the  remarkahle  devel- 

oi)ment   in  this   nuichine  during   the  lifetinu*  of  one 

man.     8o   important    were   Alaudslay's    contributions 

that   he  may  well  be  termed   the   lather  of   modern 

machine  tools.     The  back  gears  used  to  inci*ease  the 

power  of  the  drive  were  inventcnl  by  Ivichard  liobert- 

about    1817.     From   18.*)()  onward  there  was   little  <1< 


LATJIKS 


2( !:'. 


via.  4().     spi:i:i)  lathe 

olivtT  Macl.iucry  (N>. 

velopment  in  the  essential  design  of  the  turning  lathe 
iinlil,  about  2:)  yc^-irs  later,  the  turret  lathe  was  de- 
veloped, and  later  still  the  automatic  turret  lathe. 
I'oth  of  these  are  American  in  their  origin. 

The  Speed  Lathe.— The  sinrph^st  form  of  lathe  used 

''May  is  the  speed  lathe,  Figure  46,   which  consists 

'I   a   bed  having  guides  or  ways  on  its  top,  and  at 

nc  end— invariably  the  left-hand  end  as  the  workmen 

'<M's  the  machine— a  headstock,  or  casting,  contain- 

i;  two  bearings.    In  these  bearings  is  the  live  spin- 


f 


2ai 


THE  MECHANICAL  EQUIPMENT 


die,  and  between  the  bearings  is  a  pulley,  called  the 
cone  pulley  from  its  step-like  form,  which  is  used  to 
drive  the  work.  At  the  right-hand  end  is  the  tail- 
stock,  which  contains  the  dead  center,  on«  of  the 
conical  points  on  which  the  work  turns.  The  front 
of  the  driving  spindle  contains  the  other  center, 
which  is  known  as  the  live  center,  because  it  rotates 
with  the  live  spindle.  It  is  highly  important  that  this 
should  run  true,  or  it  will  cause  the  work  to  revolve 
in  an  eccentric  path. 

On  the  end  of  the  live  spindle  just  back  of  the 
center  is  a  flat  plate,  called  the  face  plate,  which,  for 
metal  turning,  is  notched.  The  work  is  mounted  on 
these  two  centers,  and  a  projection,  usually  the  horn 
of  a  lathe  dog  secured  to  the  work,  engages  with 
this  notch.  The  turning  force  is  transmitted  through 
the  live  spindle,  the  notch  in  the  face  plate  and  the 
dog,  to  the  work,  which  rotates  freely  about  the  axis 
of  the  two  centers.  An  adjustable  slide  carries  a 
light,  straight  rest,  which  is  set  parallel  with  the 
work,  and  a  hand  tool  resting  on  this  support  close 
to  the  piece  turned,  is  manipulated  by  the  operator 
to  make  the  desired  cuts.  This  form  of  lathe  is  so 
simple  that  its  construction  will  be  understood  from 
the  illustration  without  further  explanation.  Speed 
lathes  are  little  use  now  for  metal  turning;  they  are 
mainly  confined  to  pattern  shops  and  wood-working 
plants,  where  they  will  always  have  a  place,  as  the 
Avork  of  cutting  is  not  heavy  and  a  hand  tool  may  be 
used  freely  and  safely. 

The  Engine  Lathe. — The  rather  archaic  name  of 
*' engine"  lathe  still  clings  to  the  standard  type  of 


LATHES 


200 


i) 


metal-cutting    lathe    which    is    power    driven    and 
equipped  with  a  slide  rest  and  screw-cutting  attach- 
ment.    The  principal  elements  of  the  engine  lathe, 
Figure  47,  are  the  bed,  headstock,  spindle,  back  gears, 
tail  stock,  slide  rest  or  carriage,  apron,  a  lead  screw, 
change    gears,    and    feed    rod.      Auxiliary    attach- 
ments that  go  with  the  lathe  are  the  chuck,  steady 
rest  and  follower,  dogs,  taper  attachment,  and  boring 
bar.    The  lathe  bed  is  the  main  frame  that  carries 
the   working  parts.    For   small   and   moderate-sized 
lathes  this  is  carried  on  legs  at,  or  near,  each  end. 
Frequently  one  of  these  legs,  usually  the  left-hand 
one,  IS  expanded  into  a  box  or  chest. 

It  is  desirable  to  have  the  center  line  at  a  level 
convenient  for  operation.     Consequently,  as  the  size 
of  lathes  increases,  the  bed  becomes  lower,  the  legs 
shorter,  and  finally,  in  the  largest  sizes,  the  legs  dis- 
appear altogether  and  the  bed  rests  directly  on  the 
foundation.     (See  Figure  53.)     Generally  the  cross- 
section  of  the  bed  consists  of  two  parallel  girders  ap- 
proximately of  an  I-section,   braced   across   at 'fre- 
quent intervals.    On  the  tops  of  these  girders  are  the 
ways,    which    in    America    are    inverted    V-shaped 
guides.    The  European  tool-makers  prefer  flat,  square 
shdes,  but  the  universal  practice  in  the  United  States 
IS  to  make  the  ways  of  inverted  V-section.     There  are 
two  sets  of  these  ways,  one  on  each  side;  the  outer 
pair  carry  the  slide  rest,  and  the  inner  pair  the  head- 
and  tail-stocks.    In  some  Iatlie.=5  a  single  V  is  used  for 
one  side  of  the  slide  rest;  the  other  side  resting  on  a 
flat  surface.    In  small  and,  medium  sizes,  it  is  quite 
common  to  have  an  oil  pan  for  catching  oil  and  chips 


I 

I 


206 


» 

W 
H 


o 

G 


d 


LATHES 


207 


running  the  entire  length  of  the  lathe,  which  may 
or  may  not  be  a  part  of  the  main  casting.  The  bed 
should  be  not  only  strong  enough  to  carry  the  bending 
and  twisting  strain  due  to  the  cutting  action,  but 
stiff  enough  to  have  no  appreciable  springing  even 
under  the  heaviest  load.  The  ways  must  be  straight 
and  truly  parallel,  and  the  head-  and  tail-stocks 
parallel  and  in  line. 

Head-Stock.— The  head-stock  at  the  left-hand  end 
of  the  lathe  is  either  cast  or  otherwise  permanently 
secured  to  the  bed.    It  carries  the  live  spindle  and 
the  driving  mechanism.    A  cross-section  of  a  head- 
stock  is  shown  in  Figure  48.    It  has  two  adjustable, 
accurately  made  bearings  in  which  the  live  spindle 
runs.    This  is  driven  by  a  large  gear.  A,  which  is 
keyed   to   it.     The   stepped   driving   pullev,  P,   runs 
freely  on  this  spindle;  when  the  lathe  is  used  for 
light  fast  cuts  a  locking  pin,  B,  secures  the  cone  pul- 
ley to  the  gear.  A,  and  drives  the  spindle  direct.    For 
heavy  cuts,  when  slow  speed  and  great  power  are 
needed,  the  back  gears  are  used.     These  are  shown 
in  Figures  47  and  48.     They  are  usually  on  the  same 
level  as  the  spindle   and   directlv  behind   it,  as  in 
Figure  47.    In  Figure  48,  they  are  drawn  in  a  false 
.  position  above,  in  order  to  bring  them  into  the  plane 
with  the  picture.    The  bearings,  c,  for  the  back  gear 
shaft  are  part  of  the  head-stock,  and  the  shaft,  which 
is  an  eccentric,  carries  the  two  gears,  b  and  c. 

Speeds.— When  the  spindle  is  driven  directly  by 
the  pulley,  as  described  above,  the  eccentric  shaft  is 
turned  back,  and  the  back  gears  are  thrown  out  of 
mesh  with  the  gears,  d  and  A;  otherwise  the  mechan- 


.'11 


\\i\. 


208 


THE  MECHANICAL  EQUIPMENT 


^ 


0-. 


.-b 


.■  Eccentric 


C-.      ..a 

-JL. 


^^ 


FIG.  48.      CROSS-SECTION  OF  HEAD  STOCK 
Pratt  &  Whitney  Co. 

ism  would  lock  and  be  inoperative.  When  the  slow 
speeds  are  required,  the  locking  pin,  B,  is  withdrawn 
so  that  the  cone  is  no  longer  connected  with  the 
driving  gear,  A,  aad  is  free  to  rotate  on  the  spindle. 
The  eccentric  back-gear  shaft  is  then  turned  forward 
to  the  position  shown  in  Figure  48,  throwing  the 
larger  of  the  back  gears  into  mesh  with  the  gear,  d, 
carried  on,  and  rotating  with,  the  cone  pulley,  and 
throwing  the  smaller  one,  c,  into  mesh  with  the  main 
driving  gear.  A,  on  the  spindle.  The  power  is  then 
transmitted  around  through  the  back  gears  and  back 
on  to  the  spindle.    If  there  are  four  steps  on  the  cone 


LATHES 


209 


pulley,  as  shown  in  Figure  48,  four  speeds  are  pos- 
sible on  the  direct  drive,  and  if  the  lathe  is  thrown 
*4nto  back  gear"  four  more  are  possible.  The  speed:; 
are  usually  so  arranged  as  to  be  in  geometrical 
progression.  With  very  large  and  heavy  lathes  there 
i::ay  be  two  back-gear  shafts— such  lathes  are  said  to 
be  tripled-geared.  Between  the  cone-pulley  gear  and 
the  left-hand  bearing  is  a  small  gear,  e,  keyed  to  the 
driving  spindle  from  which  the  feed  mechanism  is 
taken. 

Spindle  and  Tail  Stock.— The  main  driving  spindle 
is  usually  hollow.    This  permits  cutting  operations  on 
bar  stock  which  is  slipped  in  through  the  left-hand 
end  of  the  spindle  and  is  grasped  by  the  hollow  tube 
shown.     This  tube  has  on  its  right-hand  end  spring 
jaws,  f,  which  are  drawn  together,  clamping  the  bar 
close  to  the  cutting  point  when  the  hand  wheel  at  the 
extreme  left  is  turned.    Instead  of  this  spring  collet, 
as  it  is  called,  a  solid  plug  may  be  used,  and  the  sur- 
rounding collar,  g,  engaging  it  may  be  split.    The 
hand  wheel  may  then  be  used  to  spread  the  collar  so 
that  it  can  be  used  as  an  expanding  chuck  to  hold 
and  center  work  that  has  a  hole  in  it,  the  piece  being 
slipped  over  the  collar  and  the  collar  expanding  until 
the  work  is  firmly  held.     The  tail-stock  is  shown  on 
the  right  in  Figure  47.     This  is  adjustable,  as  a  whole, 
lengthwise  on  the  ways  of  the  bed  to  accommodate 
different  lengths  of  stock.    A  finer  adjustment  of  the 
dead  center  is  operated  by  the  hand  wheel,  h,  at  the 
extreme  right.    After  the  work  is  set,  the  handle,  i, 
on  the  top  of  the  tail-stock  locks  the  center  in  posi- 
tion. 


1, 

i', 


210 


THE  MECHANICAL  EQUIPMENT 


Slide  Rest.— The  slide  rest,  or  carriage,  shown  be- 
tween the  head-  and  the  tail-stock,  carries  the  tool 
post  which  holds  the  cutting  tool.  The  rest  has  a 
motion  lengthwise  of  the  bed  and  may  be  operated 
by  the  hand  wheel,  j,  or  by  a  clutch  mechanism,  which 
engages  the  feed  rod,  k,  and  throws  in  the  power 
feed.  The  rate  of  the  power  feed  may  be  controlled 
by  changing  the  gears  at  the  left-hand  end  of  the  ma- 
chine. For  screw-cutting,  a  screw,  1,  is  provided 
known  as  the  lead  screw,  which  gives  the  required 
traverse  to  the  carriage.  The  same  screw  might  be 
used  for  the  feed  and  for  thread-cutting,  but  as 
thread-cutting  is  an  accurate  operation,  this  function 
is  dissociated  from  ordinary  feeding  and  performed 
by  a  separated  lead  screw.  The  proper  rotation 
necessary  to  give  the  cutting  tool  the  required  feed  is 
obtained  through  change  gears. 

Change-Gear  Box.— In  the  standard  type  of  engine 
lathe  used  for  many  years  the  change  gears  were 
exposed  at  the  left-hand  end  of  the  lathe,  as  in  Figure 
47.  In  the  more  modern  lathes  these  gears  are  col- 
lected in  a  *' change-gear  box"  at  the  side  and  in 
front  of  the  headstock,  and  the  handle,  a,  shown  in 
Figure  49,  which  projects  forward,  enables  the  opera- 
tor to  make  a  rapid  selection  of  the  proper  combina- 
tion of  gears  required  to  give  the  lead  desired.  The 
two  handles  to  the  right  of  the  gear  box  operate  the 
change  gear  for  the  feed.  The  apron  is  the  flat  plate 
mounted  on  the  slide  rest  which  drops  down  over  the 
front  of  the  bed  and  carries  the  various  feed  attach- 
ments that  connect  the  feed  rod  and  lead  screw  with 
the  carriage.    A  proper  combination  of  the  change 


^%/j\ 


U'r''. 


!;;- 


\ 


FIGS.   49   AND   50.      HIGH-DUTY  LATHE 

^inti^^^n  ^^^^  Shows  a  24-inch  lathe  with  8-speed  geared  lead  for 

single  pulley  belt  drive.     Below  is  shown  details  of  carriage,  tool 

post,  and  follow  rest  of  a  Pratt  &  Whitney  Lathe. 

211 


210 


TJIK  MHCHANirAL  EQriPMKNT 


Slide  Rest.— The  slido  i-est,  or  carriage,  shown  l)e- 
tweon  tlu'  head-  and  Ww  tail-stock,  carrios  the  tool 
post  wliich  holds  tlu'  cutting-  tool.  The  rest  has  a 
motion  iengtiiw  isc  ol*  the  hed  and  may  he  operated 
by  the  hand  wheel,  j,  or  l)y  a  clutch  mechanism,  which 
en.iia.«;es  the  I'vrd  rod,  k,  and  throws  in  the  power 
feed.  The  rate  of  the  \n)\\vv  teed  may  he  controlled 
hy  chanuiiii;-  the  gears  at  the  left-hand  end  ot*  the  ma- 
chitie.  For  scn^w-cutting,  a  screw,  1,  is  ])r()vide(l 
known  as  the  lead  screw,  which  gives  the  reciuired 
traverse  to  the  carriage.  The  same  screw  might  he 
ii^i^d  for  the  feed  an<l  for  thread-cutting,  hut  as 
threatl-cutting  is  an  accurate  operation,  this  function 
is  dissociated  from  ordinary  feiuling  and  i)erronne(l 
hy  a  sei)ai-ated  lead  screw.  The  proper  rotation 
necessary  to  give  the  cutting  tool  the  reciuired  feed  is 
ohtained  through  change  gears. 

Change-Gear  Box.— In  the  standard  type  of  engine 
lathe  used  for  many  years  the  change  geai's  were 
exi)ose(l  at  the  left-hand  end  of  the  lathe,  as  in  Kigun^ 
47.  In  the  more  modern  lathes  these  gears  are  col- 
lected in  a  ''ehange-g(^ar  box''  at  the  side  and  in 
Front  of  tlie  headstock,  and  the  handle,  a,  shown  in 
Figure  V.\  which  ])r(>jects  forward,  enables  the  ojiera- 
tor  to  mak<'  a  rapid  selection  of  the  i)roper  combina- 
tion of  gears  recjuired  to  giv(^  the  lea<l  desired.  The 
two  handles  to  the  right  of  the  gear  box  operate  the 
change  gear  for  the  feed.  The  ai)ron  is  the  flat  plate 
mounted  on  the  slide  rest  which  droi)s  down  over  the 
front  of  the  l)«'d  and  cari-ies  the  various  feed  attach- 
ments that  connect  the  W^i^d  rod  and  lead  screw  with 
the   can-iage.     A   ])roper  conibimitiou   of   the   change 


FKJS.    49   AND   ;")().       HKJJI-DITV   LATUK 
•yipiH'i-  vitnv  shows  a  L'4-iiicli  lathe  with  S-siKvd  ^-caivd  lead  foi 
^it  i.ullev  hell   drive.     IJelow   is  sh(.\vn   (h'tnils  of  carria.ue,   too 


])ost.  and  t\.llo\v  ivsr  of  a   I'l-ait  iV:  Whiinc.v  l.alhe. 

I'll 


212 


THE  MECHANICAL  EQUIPMENT 


gears  will  permit  the  cutting  of  either  right-  or  left- 
hand  screw  threads.  The  cone  pulley  is  driven  from 
a  countershaft  which  is  usually  hung  from  the  ceil- 
ing over  the  lathe  and  carries  a  similar  cone  with 
the  ends  reversed  from  the  one  on  the  lathe  spindle. 
Single  Driving  Pulley.— One  of  the  recent  develop- 
ments in  tool  construction  is  the  use  of  a  single 
driving  pulley  running  at  a  constant  speed.  The 
speed  variations  of  the  lathe  spindle  are  obtained  by 
additional  gearing  in  the  head-stock  casing  operated 
by  the  levers,  b,  shown  on  the  front  of  the  casing 
above  the  change  gear  box  in  Figure  49.  Lathes 
equipped  with  this  type  of  drive  do  not  need  a  cone 
pulley  countershaft,  and  they  are  especially  adapted 
to   individual  motor   drives   with   a   constant-speed 

motor. 

Mounting  the  Work.— The  work  is  ordinarily 
mounted  on  the  centers  carried  in  the  head-  and  tail- 
stocks.  The  piece  is  driven  through  a  lathe  dog,  m, 
Figure  47,  which  is  clamped  on  the  piece  and  has  an 
arm  that  is  bent  to  the  left  and  engages  a  slot,  n,  in 
the  faceplate,  shown  in  Figures  47  and  50.  For  short 
pieces  the  tail-stock  is  frequently  not  used.  In  this 
case  the  face  plate  on  the  end  of  the  live  spindle  is 
replaced  with  some  form  of  chuck  similar  to  that 
shown  in  Figure  51.  In  such  chucks,  a  long  bar  of 
stock  is  put  through  the  hole  in  the  spindle  and 
grasped  by  the  three  jaws,  or  short  pieces,  which 
have  a  hole  through  them,  may  be  carried  on  the 
stepped  faces  shown  on  the  jaws.  The  steps,  a,  a', 
are  used  to  decrease  the  amount  of  motion  that  it  is 
necessary  to  give  the  jaws,  these  being  arranged  to 


LATHES 


213 


FIG.    51.      LATHE    CHUCK 

have  a  motion  little  more  than  the  distance  between 
steps.  If  the  work  is  slightly  smaller  than  the  capac- 
ity of  the  outermost  step,  a,  the  jaws  are  run  out  and 
the  second  set  of  steps,  a',  is  used— and  so  on  to  the 
smallest  set,  a". 

In  the  simplest  form  of  chucks,  each  jaw  is  oper- 
ated by  an  independent  screw  on  the  periphery  of  the 
chuck.  This  entails  care  and  time  on  the  part  of  the 
workmen  in  centering  work.  In  the  more  refined 
forms  of  chucks,  all  of  the  jaws  are  operated  from 
any  one  of  the  adjustling  screws,  b,  there  being  one 
opposite  each  jaw,  so  that  they  may  be  moved  in  and 
out  simultaneously  from  whichever  adjusting  screw 
liappens  to  be  in  the  front  of  the  chuck.  In  many 
chucks,  the  jaws  are  reversible  in  the  head  so  that 


,1..' 


'<! 


4 


I'      ■■    i 


214 


THE  MECHANICAL  EQUIPMENT 


they  may  be  used  for  exterior  as  well  as  interior 
work. 

Tool  Post. — The  construction  of  the  tool  post,  o,  is 
clearly  indicated  in  Figures  47  and  50.  The  slide  rest 
that  carries  it  has  a  feed  lengthwise  of  the  bed  as  a 
part  of  the  general  movement  of  the  carriage,  and  a 
crosswise  feed  operated  by  the  handle,  p,  shown  in 
front.  Compound  slides  are  arranged  to  swivel  at  an 
angle  horizontally,  and  have  an  independent  power 
feed  for  the  tool  post  at  this  angle.  This  gives  a 
convenient  means  of  turning  conical  surfaces.  Long 
cones  or  tapers  are  cut  much  more  accurately  by 
what  is  known  as  the  taper  attachment.  This  con- 
sists of  a  straight  edge,  carried  usually  at  the  back 
of  the  bed.  The  cross  slide  carrying  the  tool  post  is 
attached  to  a  block  sliding  on  this  straight  edge.  If 
the  straight  edge  is  set  at  the  desired  angle,  the  tool 
post  will  move  in  and  out  uniformly  as  the  carriage 
is  fed  lengthwise,  thus  generating  very  accurately  the 
taper  desired. 

In  long,  slender  work  it  is  desirable  to  guide  the 
piece  between  the  centers,  to  prevent  its  springing 
tinder  the  pressure  of  the  cutting  tool.  For  this  pur- 
pose a  steady  rest  is  provided,  similar  to  the  one 
shown  at  c  in  Figure  49,  which  consists  of  a  circular 
frame  with  three  sliding  pieces  that  can  be  adjusted 
in  and  out  from  the  center  to  bear  on  the  work  and 
hold  it  in  position.  It  is  often  better  to  have  the 
guide  close  to  the  tool,  and  to  follow  it  as  it  makes 
the  cut.  In  this  case,  it  is  called  a  follow  rest  and  is 
mounted  on  the  carriage  directly  behind  the  cutting 
tool,  as  shown  in  a  modified  form  in  Figure  50. 


LATHES 


215 


Special  Lathes.^There  are  many  forms  of  lathes 
designed  for  special  purposes,  the  proportions  of 
which  differ  materially  from  those  shown.  A  gap 
lathe  is  one  with  a  gap  or  sag  in  the  bed  in  the  zone 
of  the  face  plate  which  gives  a  combination  lathe 
capable  of  turning  long  work  of  small  diameter,  or 
short  work  of  large  diameter.  Another  type  of  lathe 
has  two  sets  of  centers  at  different  heights  from  the 
bed.  For  work  of  small  diameters  the  lower  set  of 
centers  is  used,  and  for  an  occasioal  job  of  large 
diameter  the  upper  set  of  centers  is  employed.  Such 
a  tool  is  essentially  a  jobbing  machine,  and  is  not  to 
be  recommended  for  ordinary  work. 

Figure  52  shows  a  car-wheel  lathe,  for  turning  loco- 
motive driving  wheels.  In  this  lathe  the  tail-stock 
has  been  replaced  with  another  head-stock  and  there 
are  two  tool  posts  so  that  the  wheels,  mounted  on  the 
axles,  are  swung  on  centers  and  driven  from  both 
sides,  and  cuts  are  taken  on  each  wheel  simul- 
taneously. This  view  shows  the  type  of  face  plate 
used  on  large  lathes,  with  T-slots  in  the  face,  which 
are  used  to  secure  the  work.  Figure  53  shows  a  lathe 
of  the  very  largest  type  used  for  boring  and  turning 
a  100-inch  gun.  This  machine  is  over  185  feet  long, 
each  carriage  weighs  125  tons,  and  the  complete  ma- 
chine weighs  800,000  pounds. 

Lathe  Operation.— Care  should  be  used  in  drilling 
the  center-holes  that  are  to  carry  the  work.  These 
should  be  concentric,  and  the  conical  surfaces  that 
bear  on  the  lathe  centers  should  be  cut  at  the  same 
angle  as  the  centers.  It  is  often  necessary  to  do  turn- 
ing operations  that  shall  be  concentric  with  a  hole 


FIGS.    52    AND    53.      ABOVE:     CAR    WHEEL    LATHE.     BELOW: 

LARGE   GUN   LATHE 
216  Niles-Bement-Pond  Co. 


LATHES 


217 


already  formed  in  the  piece.  Work  of  this  character 
is  often  done  on  an  arbor,  which  is  a  bar  carried 
on  the  lathe  centers  and  driven  from  the  face  plate. 
The  piece  is  mounted  directly  on  this  arbor,  which 
may  be  made  expanding,  to  grasp  the  work  in  a  man- 
ner similar  to  that  described  in  connection  with  the 
chuck.  If  they  are  properly  mounted,  the  subsequent 
operations  will  have  a  correct  relationship  to  the 
bored  hole.  Pieces  too  large  for  a  chuck  which  are 
comparatively  short  and  large  in  diameter,  are 
clamped  directly  to  the  face  plate  by  means  of  the 
T-slots  already  referred  to. 

Boring  may  be  done  on  the  turning  lathe  by  mount- 
ing the  work  on  the  face  plate  and  reaching  in  from 
the  end  with  a  boring  tool  carried  in  the  tool  post. 
This  can  be  done,  however,  only  for  holes  that  are 
readily  accessible  from  one  end.  When  the  hole  is 
long,  the  work  may  be  mounted  on  the  carriage  and 
a  cutting  tool  may  be  mounted  on  a  bar  carried  be- 
tween the  two  centers  and  driven  from  the  face  plate. 
If  the  carriage  is  moved  along  the  bed,  the  work 
may  be  fed  past  the  tool,  and  the  hole  may  be  bored. 
Large  lathes  may  be  fitted  with  a  special  boring  bar 
provided  with  means  of  feeding  the  cutting  tool  along 
Its  length.  In  this  case,  the  work  is  clamped  to  the 
athe  bed  and  the  tool  is  fed  past  it.  In  general, 
however,  work  of  this  character  is  performed  on 
bormg  machines,  which  are  more  conveniently 
adapted  to  this  type  of  operations. 

Eccentric  work,  such  as  crankshaft  pins,  may  be 
turned  on  a  lathe.  The  ordinary  lathe  can  turn  only 
round  work  that  is  concentric  with  the  live  spindle 


>'"^^Sc. 


lit 


.»2     AM) 


■  )■). 


.lUJ 


\lU)Vi::      CAR     WUKF.L     LNTIII 

LAK<;i:  iivs  lathi: 

Nih's-HcMiUMil-I'ni:*)   ( 'o. 


HKi.inv 


LATHES 


217 


already  formed  in  the  piece.     Work  of  tins  diameter 


IS  often  done  on  an   arl 


)or,   wliicli    is   a    bar   cirried 


on  tlie  lathe  ecntcrs  and  d 


riven   from  the  face  j)late 


The  piece  is  mounted   diivetly  on   this  arbor,   which 
may  he  made  expandinjL--,  to  <;ras])  the  work 


111  a  man- 


in  ('oniH'ction   with   tiie 


ner  similar  to  tliat  (h'scrihed 

chuck,     if  tliey  are  properly  inoiinted,  the  snhsiwjueiit 

operations    will    have   a    correct    ivlationship    to    the 

hored   hole.     Pieces  too  1 

comparatively    short     and     lar 

clamped  directly  to  the  face  ])late  hv   means  of  the 


ur^e  for  a  chuck   which  are 
U(^     in    diameter,    ai'e 


T-slots  alreadv  referred  to 


I 


Torino-  may  he  done  on  the  turninu-  lathe  I 


)v  mount- 


mi;-  the  work  on  the  f 


:ice  plate  and   reachiiii;  in  I'l 


om 


tli<*  ^nu\  with  a  horino-  tool  carried  in  the  tool  post 
This  can  be  done,  however,  only  for  holes  Hint  are 
ivadily  accessible  from  one  end.  When  the  hole  is 
Ion.!*-,  the  work  may  be  mounted  on  the  carria.nc  and 
a  cuttino-  tool  may  be  mounted  on  a  bar  carried   be- 

ind  driven  from  the  face  ])late. 

le    work 
e  mav  be  bored. 


tween  the  two  center 


ir  tl 


le   carria<'e   is   moved   alono-   tin*    bed,   tl 


may  be  \\h\  past  the  tool,  and  the  hoi 


f 


irii'e 


latli 


es  may  be  fitted  with  a  special  borino   | 
JHovided  with  means  of  feeding-  the  cuttiim-  tool  al 


»ar 


'ts  leiii»-th.     In  tlii 


on 


(V 


s  cas(s  tli(^  work  is  clamiM^l  to  the 


I'lthe    bed   and    the   tool    is    Uh\   past    it.     1 


Ik 


•wever,    work    of    this    charact 


'»'ini»-     machine 


which 


Japted  to  this  tvne  of 


n    i^cneral, 
er    is    iJerfoj-iiied    on 
are     more     conveniently 


pe  ot  operations. 


I^>centi*ic   work,  such   a 
'ned  on  a  lathe.     The  ord 


nid   work  that    is  r 


crankshaft   pins,   may  be 
inary  lathe  can  turn  only 

ive   si)iFMlh'. 


oncentric  with   the   | 


218 


THE  MECHANICAL  EQUIPMENT 


To  turn  a  crankshaft  pin,  therefore,  the  main  body 
of  the  crank  is  set  **off  center''  by  an  amount  equal 
to  the  crank  throw,  and  firmly  clamped  in  that  posi- 
tion. This  puts  the  portion  to  be  turned  in  line  with 
the  lathe  centers. 

Spherical  work  may  be  done  on  a  lathe  if  the  work 
is  revolved  as  usual  and  the  tool  is  given  a  circular 
motion  in  a  plane  about  a  point  lying  in  the  axis  of 
the  lathe.  In  heavy  work,  frequently  several  tools  are 
mounted  on  the  tool  post,  one  behind  the  other,  the 
successive  tools  being  set  to  take  up  the  cut  where 
the  previous  one  left  it — the  last  is  the  finishing  tool. 
In  this  way  heavy  reductions  can  be  made  in  one  pass 
of  the  carriage. 

Knurling  is  properly  a  rolling  process,  not  a  cut- 
ting one.  This  is  performed  by  pressing  two 
hardened  steel  rollers,  mounted  in  the  tool  post, 
against  the  revolving  work  and  rolling  the  impression 
of  grooves  on  the  face  of  the  rolls  into  the  surface  of 
the  work.  The  operation  is  a  very  common  one  in 
tool  rooms  where  the  handles  of  gauges  are  roughened 
in  order  that  they  may  be  grasped  the  more  easily. 
The  small  diamond-shaped  knurling  which  is  so  com- 
mon is  done  })y  two  rollers  with  spiral  grooves,  one 
right-hand  and  one  left-hand.  The  impressions  of 
these  rollers  crossing  each  other  form  the  diamond- 
shaped  projections. 

Thread-cutting,  one  of  the  most  important  opera- 
tions performed  on  the  lathe,  will  be  taken  up  in  the 
chapter  devoted  to  that  subject. 


CHAPTER  XIV 
TUEEET  AND   AUTOMATIC   LATHES 

The  Turret  Principle.— While  the  engine  lathe  is 
one  of  the  best  machines  ever  designed  for  general  or 
jobbing  work,  its  use  requires  a  skilled  operator,  and 
the  time  required  in  changing  and  setting  tools  and  in 
measuring  length  and  depth  of  cuts  is  usually  largely 
in  excess  of  that  required  to  make  the  cuts  them- 
selves.   Both  the  skill  and  the  time  required  to  do 
lathe  work  may  be  reduced,  with  a  consequent  saving 
in  the  cost  of  production,  by  the  use  of  the  turret 
principle.     In  the  turret  lathe  a  slide  is  substituted 
for  the   tail-stock,   and   mounted    on   this   is   a   re- 
volving member,  or  turret,  which  has  certain  stops 
or  positions,  usually  from  four  to  six.    The  cutting 
tools  are  mounted  on  this  turret,  and  are  accurately 
set  with  reference  to  the  work.    The  work— which 
may  be  either  castings  or  forgings  held  in  some  form 
of  chuck,  or  barstock,  which  is  fed  through  the  hole 
m  the  live  spindle— is  carried  entirely  from  the  head- 
stock  end. 

The  sliding  carriage  is  fed  forward,  either  by  hand 
or  automatically,  to  a  definite  stop  which  limits  the 
length  of  the  cut;  the  carriage  is  then  withdrawn  and 
brought  forward  again.  This  action  indexes  the  tur- 
ret to  the  second  position,  and  brings  into  action  a 

219 


i 


Mil  Ml 


220 


THE  MECHANICAL  EQUIPMENT 


second  tool  which  has  been  definitely  set  for  the 
operation  it  performs.  The  second  motion  also  comes 
to  a  definite  stop,  set  to  correspond  to  the  second  cut 
and  independent  of  the  one  previously  made.  Suc- 
cessive movements  of  the  carriage  bring  the  other 
tools  mounted  on  the  turret  into  action  in  a  similar 
way;  each  motion  has  a  definite  stop  arranged  for 
that  cut.  In  most  turret  lathes  auxiliary  side  tools 
are  carried  to  definite  stops  on  a  cross  slide  mounted 
on  the  bed  between  the  head-stock  and  the  turret, 
which  may  also  be  either  hand-operated  or  automatic. 

Turret  Lathe  vs.  Engine  Lathe. — The  use  of  this 
turret  principle  greatly  reduces  the  time  necessary 
to  set  the  tools  and  so  on.  With  an  engine  lathe  the 
operator  will  place  the  tool  in  the  tool  post,  after  the 
work  has  been  properly  mounted  on  the  face  plate, 
will  make  a  trial  cut,  caliper  the  piece,  adjust  the 
tool,  and  repeat  the  process  until  the  correct  size  is 
reached.  He  will  then  start  the  cut.  As  he  ap- 
proaches the  end  of  the  cut,  he  will  stop  the  machine 
and  measure  the  work  to  see  whether  the  cut  is  long 
enough  or  deep  enough,  repeating  the  process  until 
the  correct  length  of  cut  has  been  made.  Whenever 
it  is  necessary  to  change  the  tool  to  perform  some 
other  type  of  operation,  the  whole  process  must  be 
repeated.  This  round  must  be  gone  through  for 
every  piece  made,  and  it  is  this  work  which  is 
eliminated  by  the  turret  lathe. 

In  the  latter  type  of  lathe  the  various  cutting  tools 
are  placed  in  position  by  the  tool-setter,  who  is  a 
skilled  man.  This  work  is  done  with  care,  and  one  or 
two  trial  pieces  are  run  through.    When  the  machine 


TURRET  AND  AUTOMATIC  LATHES  221 

has  been  -set  up,-  it  is  turned  over  to  the  machine 
operator  who  has  only  to  clamp  the  successive  pieces 
m  the  chuck  and  feed  the  turret  and  tools  forward  to 
make^  the  cuts.    In  the  case  of  automatic  lathes  for 
bar  stock,  he  does  not  even  have  to  do  the  latter.    His 
work  becomes  merely  that  of  keeping  the  bars  sup- 
plied to  a  number  of  machines,  each  of  which  will 
automatically  feed  forward  the  required  amount  of 
bar  stock,  clamp  it,  perform  the  successive  opera- 
ions,  cut  off  the  finished  piece,  and  feed  forward 
stock  for  the  next  piece.    The  work  of  setting  the 
tools   and   measuring   the   length   of  feed  is   conse- 
quently done  but  once-by  the  tool-setter-and  the 
cost  of  doing  It,  instead  of  being  carried  by  each 
piece  as  in  the  case  of  the  engine  lathe,  is  distributed 
over  the  entire  run. 

Hand  and  Automatic  Turret  Lathes.-The  turret 
rm  ^V^'  *"■'*  '^^'"^'  improvement  on  the 
Roberts,  and  others.    There  were  probably  a  number 

mnl'l  T'f'"^^  "*"  *^*  ^"'■'•^t  P""«'Pi«  prior  to 

nwln  . J'*  °°'  ""^'"^  ^^«  "-^S^l^riy  built  and 

placed  upon  the  market  was  brought  out  by  Jones 
&  Lamson  then  of  Windsor,  Vermont,  about  1855. 
ihe  principle  was  applied  to  the  manufacture  of  guns 

FoTThnTf  1  :  ^"**  '^^''  interchangeable  articles.' 
i"or  about  twenty  years   turret   lathes   were   hand 

teZJZ  ^}'''''P^''  ^-  Spencer,  of  Hartford,  de- 
veloped the  Idea  of  automatic  operation,  in  which  the 

«huek,  operating  the  turret  and  cross  sUde,  and  cut- 


! 


I'l 


222 


THE  MECHANICAL  EQUIPMENT 


ting  off,  were  all  controlled  by  a  single  camshaft 
mounted  in  the  body  of  the  lathe  parallel  to  its  axis 
and  making  one  revolution  for  the  complete  cycle  of 
operations.  This  invention  greatly  increased  the 
capacity  of  the  lathe  and  enabled  an  operator  to  tend 
a  number  of  machines. 

Multi-Spindle  Automatics. — The  next  increase  in 
the  capacity  of  the  lathe  came  about  twenty  years 
later,  when  Mr.  Henn  and  Mr.  Hakewessel  developed 
the  first  multi-spindle  automatics.  In  both  the  hand 
and  the  automatic  single-spindle  lathe  the  work  re- 
volved, but  remained  in  the  same  position,  and  the 
tools  were  brought  to  bear  upon  it  in  succession. 
The  time  required  to  finish  a  piece  was,  therefore, 
that  required  for  the  sum  of  the  various  operations. 
In  the  multi-spindle  automatic,  the  axis  of  the  index- 
ing member  is  horizontal,  and  parallel  to  the  axis  of 
the  lathe;  and  there  are  several  live  spindles  corre- 
sponding in  number  to  the  number  of  tool  positions. 
Each  of  these  spindles  carries  a  bar  of  stock  which 
is  being  operated  upon,  and  all  the  tools  are  cutting 
simultaneously.  "When  the  longest  cut  is  finished, 
either  the  tools  or  the  spindles  are  rotated  to  the 
next  position  and  the  operation  is  repeated.  A  bar 
is  fed  forward  for  the  first  operation,  and  then  in- 
dexed progressively  through  the  successive  positions 
until  the  piece  is  completed.  Either  the  tools  or  the 
spindles  may  be  indexed.  With  this  type  of  lathe, 
the  time  required  to  finish  the  piece  is  reduced  from 
the  total  time  of  all  the  operations  to  the  time 
required  for  the  longest  individual  operation  on  the 
piece. 


TURRET  AND  AUTOMATIC  LATHES 


223 


Hand-Operated  Turret  Lathes.— Of  the  various 
types  of  turret  lathes,  the  simplest  is  the  plain  hand- 
operated  machine,  shown  in  Figure  54.  This  is  used 
for  small  and  light  work.  In  the  one  illustrated,  the 
oil  pan  and  bed  are  in  one  casting.  As  stiffness  and 
perfect  alignment  are  essential  in  all  turret  work, 
the  head  is  also  frequently  cast  solid  with  the  bed, 
although  the  one  shown  is  a  separate  casting.  To 
increase  the  stiffness,  the  small  end  of  the  cone  pulley 
is  pointed  toward  the  right,  which  permits  a  firmer 
support  for  the  main  bearing  of  the  spindle.  The 
spindle  bearings  are  babbitted.     Two-speed  counter- 


FIG.    54.      HAND-OPERATED    TURRET    LATHE 
Pratt  &  Whitney  Co. 


222 


THE  MECHANICAL  EQUIPMENT 


ting  off,  were  all  controlled  by  a  sinp'le  eamsliaft 
mounted  in  the  body  of  the  lathe  parallel  to  its  axis 
and  making  one  revolution  for  the  complete  cycle  of 
operations.  This  invention  greatly  increased  the 
capacity  of  the  lathe  and  enabled  an  operator  to  tend 
a  numl)er  of  machines. 

Multi-Spindle  Automatics. — The  next  increase  in 
the  capacity  of  the  latlie  came  al)out  twenty  years 
later,  when  ^Ir.  Henn  and  Mr.  TTakewessel  developed 
the  iirst  multi-spindle  automatics.  In  both  the  hand 
and  the  automatic  single-spindle  lathe  the  work  re- 
volved, but  remained  in  the  same  position,  and  the 
tools  were  brought  to  bear  upon  it  in  succession. 
The  time  required  to  finish  a  piece  was,  therefore, 
that  reciuired  for  the  sum  of  the  various  operations. 
Tn  the  multi-spindle  autonuitic,  the  axis  of  the  index- 
ing member  is  horizontal,  and  parallel  to  the  axis  of 
the  lathe;  and  there  are  several  live  spindles  corn^- 
sponding  in  number  to  the  number  of  tool  i)()sition>. 
Each  of  these  spindles  carries  a  bar  of  stock  which 
is  being  operated  upon,  and  all  the  tools  are  cuttini; 
simultaneously.  "When  the  longest  cut  is  finishiMl, 
either  the  tools  or  the  spindles  arc  rotated  to  tlic 
next  position  and  the  operation  is  repeated.  A  bar 
is  fed  forward  for  the  first  operation,  and  then  in- 
dexed progressively  through  the  successive  position-^ 
until  the  piece  is  completed.  Either  the  tools  or  tii^' 
spindles  may  be  indexed.  With  this  type  of  latins 
the  time  required  to  finish  the  piece  is  reduced  tVoni 
the  total  time  of  all  the  operations  to  the  ti;!!^' 
required  for  the  longest  individual  operation  on  ii<' 
piece. 


rrUKET  AM)  ACTOMATlC  LATHES 


22'] 


Hand-Operated  Turret  Lathes.— Of  th('  various 
types  of  turret  lathes,  the  simplest  is  the  plain  hand- 
operated  niacliiii(%  shown  in  Figure^  r)4.  This  is  used 
for  small  and  light  work.  Jn  the  one  illustrated,  the 
oil  pan  and  bed  are  in  one  casting.  As  stiffness  and 
perfect  alignment  are  essential  in  all  turret  work, 
the  head  is  also  frequently  cast  solid  with  the  bed, 
although  the  one  shown  is  a  separate  casting.  To 
increase  the  stiffness,  the  small  end  of  the  cone  pulley 
is  pointed  toward  the  right,  which  permits  a  firmer 
support  for  the  main  ])earing  of  the  spindle.  The 
spindle  bearings  are   babbitted.     Two-speed  counter- 


HAXn-OPKKATKl)    TrWRKT    i.ATin; 
Prat  I  &  wiiiiiu'.v  (\». 


224 


THE  MECHANICAL  EQUIPMENT 


shafts  are  used  either  for  forward  and  reverse  or  for 
two  speeds  forward  when  opening  dies  are  used. 

The  turret  slide,  1,  is  mounted  in  a  block,  2,  which 
is  adjustable  longitudinally  along  the  bed  to  accom- 
modate different  lengths  of  work.  The  turret  re- 
volves on  a  conical  central  stud,  or  pin,  fixed  on  the 
turret  slide.  The  bolt  which  locks  the  turret  in  its 
various  positions  is  located  horizontally  in  the  slide, 
and  is  hardened  and  ground;  it  is  supported  for  its 
entire  length,  and  engages  the  turret  directly  under 
the  cutting  tool.  The  index  ring  on  the  turret,  which 
the  locking  bolt  engages,  is  also  hardened  and  ground 
and  is  securely  doweled  and  bolted  to  the  under  side 
of  the  turret.  The  stop  mechanism  which  limits  the 
feed  for  the  various  positions  of  turret,  is  clearly 
shown.  The  stops,  6,  are  short  steel  bars  located  on 
a  radius  in  a  steel  bracket,  3,  which  is  on  the  front  of 
the  block,  2.  An  oscillating  lever,  4,  on  the  shaft,  5, 
engages  one  or  other  of  the  adjustable  stops,  6,  ac- 
cording to  the  position  of  the  turret.  The  position  of 
the  arm,  or  lever,  4,  is  controlled  by  a  cam,  7,  on  the 
lower  periphery  of  the  turret.  As  the  turret  re- 
volves from  one  position  to  another,  this  cam,  acting 
through  the  shaft,  5,  brings  the  arm,  4,  into  position 
for  contact  with  the  proper  stop.  The  arm,  4,  is  re- 
lieved of  any  strain  by  being  backed  up  by  the  pro- 
jection, 8,  which  is  a  part  of  the  turret  slide,  1. 

In  small  machines  of  this  character  the  turret  slide 
is  operated  by  a  single  hand-lever  as  shown,  and  the 
indexing  of  the  turret  is  done  by  the  movement  of 
the  slide.  A  cross  slide,  9,  carries  the  forming  and 
cutting-off  tools,  one  in  front  of  the  work  and  the 


TURRET  AND  AUTOMATIC  LATHES    225 

other  behind  it.  The  slide  is  adjustable  lengthwise 
on  the  bed  between  the  head-stock  and  turret  slide, 
and  can  be  clamped  to  the  ways  in  the  position  de- 
sired. The  feed  of  the  slide  is  by  hand  lever  through 
a  rack  and  pinion,  and  is  accurately  governed  in  both 
directions  by  means  of  adjustable  stops.  The  bar 
stock,  which  is  not  shown  in  Figure  54,  is  fed 
forward  by  means  of  the  hand  lever  on  the  left 


FIG.  55.      MULTIPLE  BOX  TOOL 

Pushing  this  handle  to  the  left  unclamps  the  chuck 
and  moves  the  feeding  mechanism  back  along  the  bar 
the  distance  required  for  the  next  piece.  The  return 
movement  of  the  handle  brings  the  bar  forward  this 

TTr!  .  I*  *^'  '^^  ^^  *^^  ^^*i<^«  the  accurately 
Jnished  and  hardened  chuck  jaws  clamp  the  work 
concentrically  with  the  spindle 

The  cutting  tools  are  carried  in  the  holes,  10,  shown 
m  the  turret.     Two  of  these  tools  are  shown  in  Figure 

u LTi't  "^'^'  ^'  "  ^"^  ''  ^^^  characteristic  tS 
used  m  turret  work.    As  there  is  no  tail-stock  on  the 


226 


THE  MECHANICAL  EQUIPMENT 


turret  lathe,  a  heavy  side  cut  on  a  long  bar  would 
tend  to  spring  it  out  of  position.  To  prevent  this,  an 
adjustable  stop,  a,  is  provided  which  is  carried  on 
the  tool  body  immediately  opposite  the  cutting  tool, 
b.  Tools  of  this  character  are  used  in  a  wide  variety 
of  forms. 

Gisholt  Lathe.— A  turret  lathe  of  a  much  more  com- 
plex type  is  the  Gisholt  lathe,  shown  in  Figure  5b\ 
This  machine  was  a  pioneer  in  applying  the  turret 
principle  to  large  and  heavy  work,  and  is  built  in 
sizes  having  a  swing  as  large  as  41  inches.  The 
spindle  is  bored  to  enable  the  use  of  barstock,  but 
the  machine  is  more  commonly  used  on  castings  and 
forgings  held  in  a  chuck.  This  lathe  was  the  first  to 
employ  the  pilot  bar  principle  in  heavy  turret  work. 
The  pilot  bar  is  very  useful  in  relieving  the  machine 
of  much  of  the  strain  due  to  heavy  cuts. 

The  first  operation  on  the  piece  is  to  establish 
an  accurately  bored  hole  in  the  piece  to  be  machined. 
Pilot  bars,  shown  at  a  in  Figure  56  and  at  a'  in  Figure 
57,  used  with  the  succeeding  operations,  enter  this 
hole  and  center  the  cutting  tool,  b  and  b'.  The  side 
strains  between  the  cutting  tool,  b',  and  the  pilot  bar, 
a',  due  to  the  cut — which  w^ould  otherwise  extend 
dowm  through  the  turret,  along  the  bed,  up  through 
the  head,  and  out  upon  the  w^ork — are  carried  by  the 
fixture  itself.  The  machine  is  therefore  relieved  of 
these  strains,  and  the  resulting  work  is  more  accurate. 
The  axis  of  the  hexagonal  turret  is  inclined  backward 
instead  of  standing  vertical,  as  in  other  machines. 
This  is  done  to  enable  the  long  pilot  bars  and  other 
tools  to  swiKg  clear  of  the  operator  in  front.     The 


Vv 


■^1 


FIGS.  56  AND  57.      ABOVE:    TOP  VIEW  OF  A  GISHOLT  LATHE. 

BELOW;     WARNER  &  SWASEY  LATHE  227 


22(i 


TlIK  MECllANK  AL   K^^ll  PMl^NT 


furrof.  lallic,  a  lu^nvy  side  cut  on  a  loni;'  l>ar  would 
tcMid  to  spi'iii,!;  it  out  of  |)ositioii.  To  prevent  tliis,  an 
adjustable  sto]),  a,  is  ])ro\ided  wliicli  is  carrie*!  on 
the  tool  l)ody  innuediately  opposite  the  cuttini;-  tool, 
b.  Tools  of  this  charaeter  are  used  in  a  wide  variety 
of  forms. 

Gisholt  Lathe.— A  turret  lathe  of  a  nnieh  more  com- 
plex tyi)e  is  the  Oisholt  lathe,  shown  in  Figure  r)(). 
This  machine  was  a  pioneer  in  applyini;-  the  turret 
principle  to  large  and  heavy  work,  and  is  built  in 
sizes  liaving  a  swing  as  lai'ge  as  41  inches.  The 
spindle  is  l)ored  to  en.able  the  use  of  barstock,  but 
the  macliine  is  more  connnonly  used  on  castings  and 
forging?  held  in  a  chuck.  This  lathe  was  the  (irst  to 
employ  the  pilot  bar  ])rinciple  in  heavy  turret  work. 
The  pilot  bar  is  very  useful  in  relieving  the  machiTve 
of  much  of  the  strain  due  to  heavy  cuts. 

The  first  operation  on  the  ])iece  is  to  establish 
an  accnrately  bored  liole  in  the  piece  to  be  machined. 
Pilot  bars,  shown  at  a  in  Figui-e  ')6  an<l  at  a'  in  Figun^ 
57,  used  with  the  sncceeding  operations,  enter  this 
hole  and  center  the  cutting  tool,  b  and  b'.  The  side 
strains  between  the  cutting  tool,  b',  and  the  pilot  bar, 
a',  due  to  the  cnt — which  would  otherwise^  extend 
down  through  the  turret,  ah)ng  the  bed,  up  through 
the  head,  and  ont  upon  the  work — are  carried  by  th<' 
fixture  itself.  The  machine  is  therefoi-e  relieved  of 
these  strains,  and  the  resulting  work  is  more  accurate. 
The  axis  of  the  hexagonal  tui*i-et  is  inclined  bacl:war<l 
instead  of  standing  vei'tical,  as  in  otliei*  machine-. 
This  is  done  to  enable  the  long  pilot  bars  and  oth<  ;' 
tools   to   swii/^g  cleai-  of  the  o})eiator   iu    front.     Tiie 


FIGS.   56  AND  57.      ABOVE :    TOP  VIEW  OF  A  GISIIOLT  LATHE. 

BELOW:     WARXEK   &   SWASEY   LATHE  227 


I 


,'  1 


:  I 


i 


228 


THE  MECHANICAL  EQUIPMENT 


machine  is  equipped  with  a  cone  pulley  and  a  back 
gear,  and  the  head-stock  is  cast  solid  with  the  bed.  A 
sliding  carriage  between  the  head-stock  and  the  tur- 
ret has  a  revolving  tool  post,  designed  to  hold  four 
cutting  tools,  which  is  in  effect  an  auxiliary  turret. 

Any  one  of  these  tools  may  be  brought  into  cutting 
position  by  revolving  the  tool  post,  and  each  is  in- 
dependently adjustable  for  height  and  is  provided 
with  an  automatic  stop.  The  tool  post  has  an  inde- 
pendent power  cross  feed,  and  the  carriage  is  also 
fitted  with  an  attachment  for  turning  tapers,  and  w^ith 
a  support  for  rigidly  holding  boring  bars,  drills,  and 
so  on,  in  line  with  the  spindle.  This  is  so  designed 
that  when  not  in  use  it  may  be  swung  back  out  of 
position  to  clear  the  chuck.  Both  the  tool-post  car- 
riage and  the  turret  slide  are  screw-cutting,  and  the 
power  feed  may  be  varied  without  changing  the 
gears.  The  carriage  and  slide  are  also  provided  with 
clamping  devices  to  bind  them  rigidly  to  the  ways 
at  any  desired  location.  This  machine  has  been  in 
successful  use  for  many  years  and  has  had  a  wide 
influence  on  machine  shop  practice,  extending  the  use 
of  the  turret  principle  to  the  machining  of  such 
pieces  as  pistons,  cylinder  heads,  flanges,  couplings, 
and  pulleys.  The  Gisholt  Company  has  also  de- 
veloped a  lathe  in  which  the  operations  when  once 
the  piece  has  been  chucked  in  place  are  entirely 
automatic.  This  last  machine  is  of  the  single-pulley, 
one-speed  type. 

Warner  and  Swasey  Lathe.— Figure  57  shows 
another  large  turret  lathe,  built  by  the  Warner  & 
Swasey  Company.    The  turret,  or  revolving  member, 


TURRET  AND  AUTOMATIC  LATHES 


229 


in  this  machine  is  a  large,  hollow  hexagon  mounted 
on  a  saddle,  or  slide.  This  form  permits  the  attachment 
of  much  heavier  tools  than  allowed  by  the  holes  shown 
in  Figure  54.  Several  of  the  tools  shown  are  pro- 
vided with  pilot  bars  just  described  in  connection 
with  the  Gisholt  lathe.  This  lathe,  like  the  Gisholt, 
may  be  used  either  for  bar-stock  work  or  for  cast- 
ings and  forgings;  simultaneous  operations  may  be 
performed  by  the  turret  and  by  a  carriage  with  a 
square  tool  post  which  can  be  indexed  to  four  posi- 
tions. 

The  saddle,  or  main  slide,  is  mounted  directly  on 
the  bed,  and  both  the  saddle  and  the  carriage  have 
power  feeds  or  may  be  operated  by  hand  wheels;  the 
various  motions  are  controlled  by  independent  auto- 
matic stops.  The  head  and  the  bed  are  cast  in  one 
piece.  There  is  a  constant-speed,  single-pulley  drive, 
the  various  changes  of  spindle  speed  being  obtained 
by  a  gearing  enclosed  in  the  head  and  running  in  oil. 
The  machine  can  be  belted  directly  to  a  line  shaft, 
or  can  be  driven  by  a  constant-speed  motor.  The 
changes  of  feed  for  the  carriage  and  the  main  turret 
saddle  are  controlled  by  a  feed  box  at  the  head  end. 
This  lathe  will  handle  round  bar  stock  31/0  inches  in 
diameter,  or  a  maximum  of  swing  for  face-plate  work 
of  2IY2  inches.  The  maximum  length  turned  is  44 
inches,  and  the  maximum  horsepower  required  is  10. 

Hartness  Flat-Turret  Lathe.— Another  type  of  tur- 
ret lathe  is  the  Hartness  flat-turret  lathe,  which  was 
invented  about  1891  (see  Figure  58).  The  character- 
istic feature  of  this  machine  from  its  earliest  appear- 
mice  has  been  the  flat  circular  plate  mounted  on  the 


i,  ■/■'(' 


»■ 


•1 1 


h 


'r. 
.  ,i 


<i' 


230 


THE  MECHANICAL  EQUIPMENT 


saddle,  which  carries  the  various  tools  and  tool- 
holders  on  its  upper  surface,  thus  replacing  the  usual 
barrel  turret  mounted  on  a  stud  and  carrying  the 
tools  around  the  periphery.  The  advantage  of  this 
construction  is  that  the  tools  do  not  overhang  their 
support,  and  th-e  whole  construction  is  very  rigid  as 
the  flat  turret  plate  is  secured  to  the  saddle  by  an  an- 
nular clamp  which  holds  it  rigidly  at  all  points.  The 
turret  is  automatic  in  action,  turning  as  the  tools 
clear  the  work,  and  it  may  be  set  so  as  to  skip  one  or 
more  of  the  indexing  positions  when  desired. 

As  in  other  types  of  turrets,  the  locking  bolt  is  on 
the  outer  edge,  directly  under  the  cutting  tool.  In 
the  earlier  forms  of  this  lathe,  the  crosscuts  were  ob- 
tained from  a  saddle  between  the  head-stock  and  the 
turret.  In  the  later  types  the  carriage  is  done  away 
with,  and  the  head  is  provided  with  a  cross  motion. 
As  in  the  machine  just  described,  there  is  a  single- 
speed  driving  pulley,  and  the  changes  of  speed  are 
derived  from  change  gears,  which  run  in  oil  inside  the 
head  casing.  The  flat  turret,  which  gives  this  lathe 
its  advantage,  limits  it  to  work  of  moderate  diameter; 
its  natural  field  is  for  threading  and  turning  large 
studs,  bolts  and  arbors.  The  size  of  work  done 
ranges  up  to  3  inches  in  diameter  and  36  inches  in 
length. 

Instead  of  one  working  spindle  and  a  circular  tur- 
ret with  six  positions,  this  type  of  lathe  is  also  made 
with  two  working  spindles  and  a  turret  which  is 
square.  Each  face  of  the  square  turret  carries  two 
sets  of  tools,  and  two  similar  cuts  may  be  carried 
on  simultaneously.    If  the  turret  is  indexed  four  sets 


I 


H 


03 


(M 


I 


I 


230 


THE  MECllAMl'AL  EQl'IPMENT 


saddle,  wliicli  can-'u's  tlie  vai'ious  tools  and  tool- 
lioldei's  on  its  nppei-  snrfaeo,  tluis  roplacin.i;'  the  usual 
barrel  turret  mounted  on  a  stud  and  earrvini;-  the 
tools  around  the  j)eriphery.  TIk*  advantage  of  this 
construction  is  that  the  tools  do  not  overhang  their 
suppoi't,  and  the  whole  construction  is  very  rigid  as 
the  llat  turret  f)late  is  secured  to  the  sachlle  by  an  an- 
nular clamp  which  liolds  it  rigidly  at  all  points.  The 
turret  is  autonuitic  in  action,  turning  as  the  tools 
chnir  the  work,  and  it  may  be  set  so  as  to  ski})  one  or 
moi-e  of  the  indexing  positions  wh(»n  desired. 

As  in  other  tyj)es  of  turrets,  the  locking  bolt  is  on 
the  outer  iH\<i;i\  dii'eetly  under  tlie  cutting  tool.  In 
the  earlier  forms  of  this  lathe,  the  crosscuts  w(M"e  ob- 
tained from  a  saddle  between  the  head-stock  an<l  the 
turret.  Jn  the  later  types  the  carriage  is  do]w  away 
with,  and  the  head  is  provided  with  a  cross  motion. 
As  in  the  machine  just  (h\scribed,  there  is  a  single- 
speed  driving  pulley,  and  the  (*hanges  of  speed  are 
derived  from  change  gears,  which  run  in  oil  inside  tln' 
lu^ad  casing.  The  Hat  turi'et,  which  gives  this  lathe 
its  advantage,  limits  it  to  woi-k  of  moderate  diann^ter: 
its  natural  field  is  foi*  threa<ling  and  tui'uing  lai'ge 
studs,  bolts  and  arboi-s.  The  siz<*  of  wo!*k  done 
ranges  up  to  3  inches  in  diameter  and  'Mi  inches  in 
h'ngth. 

Instead  of  one  woi'king  spindle  and  a  circular  tui 
ret  with  six  positions,  this  type  of  lathe  is  also  mad<' 
with  two  working  spindles  and  a  turret  which  i- 
square.  Each  face  of  the  square  turret  carries  tw  ' 
sets  of  tools,  and  two  similar  cuts  mav  be  carrie  ! 
on  simultaneouslv.     If  the  tnr?-(M  is  in<l(»xed  four  ><• 


232 


THE  MECHANICAL  EQUIPMENT 


1 


of  tools  may  be  used.  Figure  59  shows  a  typical  set- 
up for  this  type  of  machine. 

An  automatic  chucking  and  turning  lathe  which 
has  been  very  successful,  is  the  Potter  &  Johnson 
machine,  shown  in  Figure  60.  In  this  machine, 
rigidity  for  the  turret  tools  is  sought  in  another  way. 
A  vertical  turret  is  used,  but  the  stud  or  pin  upon 
which  it  revolves  is  braced  on  the  top  by  a  heavy 
overhead  support  which  extends  back  to  the  rear  of 
the  turret  slide.  The  machine  has  a  geared  head 
with  a  single-pulley  drive,  cross  slide  with  double, 
independent,  adjustable  tool  blocks,  and  an  auto- 
matic back  facer  bar  operated  through  the  spindle. 
The  chuck  is  16  inches  in  diameter  and  the  hole 
through  the  spindle  is  3i/2  inches  in  diameter. 

Principle  of  Automatic  Lathes. — The  first  automatic 
lathe,  as  mentioned  in  the  beginning  of  the  chapter, 
was  developed  by  Spencer  for  the  Hartford  Machine 
Screw  Company.  A  later  form  of  this  lathe  is  illus- 
trated in  Figure  61  which  shows  very  clearly  the  gen- 
eral principle  underlying  the  construction  of  nearly 
all  of  the  full  automatic  lathes.  The  driving  spindle, 
cross  slide,  and  turret  are  present,  as  in  the  simple 
type  of  turret  lathe  in  Figure  54.  The  control  that 
makes  them  automatic  is  derived  from  the  long  cam 
shaft  running  through  the  frame,  parallel  to  and  be- 
low the  main  center.  This  shaft  revolves  slowly, 
making  one  revolution  for  each  complete  cycle  of 
operations.  The  large  drum  to  the  left  controls  the 
operation  of  the  mechanism  that  feeds  the  bar  stock 
forward  each  time  a  piece  is  completed.  This  feeding 
is  done  by  means  of  the  strips  bolted  on  the  face. 


i 


;   i^', 


<'l 


PIGS.    59   AND    60.      ABOVE:     HARTNESS    DOUBLE-SPINDLE    LATHE. 
BELOW:     POTTER  &  JOHNSON   LATHE 

233 


THE  MECHANICAL  EQUIPMENT 


of  tool?  may  l)o  used.  Figure  59  shows  a  typical  .set- 
up for  this  type  of  machine. 

An  automatic  chucking  and  turning  lathe  which 
has  heen  very  successful,  is  the  Potter  &  Johnson 
nuichine,  shown  in  Figure  (iO.  In  this  machine, 
rigidity  for  the  turret  tools  is  sought  in  another  way. 
A  vertical  turret  is  used,  hut  the  stud  or  pin  upon 
which  it  i-evolvcs  is  hraced  on  the  top  hy  a  heavy 
overhead  support  which  extends  hack  to  the  rear  of 
the  turret  slide.  The  machine  has  a  geared  head 
with  a  single-pulley  drive,  cross  slide  with  douhle, 
independent,  adjustahle  tool  hlocks,  and  an  auto- 
matic hack  facer  har  operated  through  the  spindle. 
The  chuck  is  16  inches  in  diameter  and  the  hole 
through  the  spindle  is  3V2  inches  in  diameter. 

Principle  of  Automatic  Lathes. — The  first  automatic 
hdhe,  as  mentioned  in  the  heginning  of  the  chapter, 
was  (U'V('h)ped  hy  Spencer  for  the  Hartford  ^lachine 
Screw  Company.  A  later  form  of  this  lathe  is  illus- 
trated in  Figure  (il  which  shows  very  clearly  the  gen- 
eral principle  underlying  the  construction  of  nearly 
all  of  the  full  automatic  lathes.  The  driving  spindle, 
cross  sli(h',  and  turret  are  present,  as  in  the  simple 
type  of  turret  lathe  in  Figure  54.  The  control  that 
makes  them  autonuitic  is  derived  from  the  long  cam 
shaft  running  through  the  frame,  parallel  to  and  he- 
low  the  main  center.  This  shaft  revolves  slowly, 
making  one  revolution  for  each  complete  cycle  oT 
operations.  The  large  drum  to  the  left  controls  the 
operation  of  the  mechanism  that  feeds  the  har  stock 
forward  each  time  a  piece  is  completed.  This  feeding, 
is  done  hy  nutans  of  tlie  strips  holted  on  the  face. 


I'lus.  59  AND  GO.     ABovi::    iiartnkss  double-spixule  lathe. 

BELOW:     I'OTTEK    &    .lOHXSON    LATHE 

233 


TURRET  AND  Al TOMATIC  LATHES 


233 


FIGS.    61    AND    62.      AUTOMATIC   SCREW    MACHINES 

Upper:   Hartford  Machine  Screw  Co.    Lower:  Brown  &  Sharpe 
234  Mfg.  Co. 


wliicli  oiigago  a  pin  in  the  nieebanism  above.  The 
plate  under  the  driving  pulleys  operates  the  belt- 
shifting  mechanism  by  means  of  the  dogs  shown  on 
the  edge.  The  timing  of  the  belt-shifting  is  accom- 
plished by  sliding  these  dogs  to  the  required  position 
around  the  edge  of  the  plate.  The  next  cam  controls 
th<?  motions  of  the  cutting-off  tool  located  in  the  slide 
immediately  above  it.  The  large  cam  to  the  right 
controls  the  motions  of  the  turret  carriage.  The 
worm  wheel  drives  the  cam  shaft,  and  the  plate  at  the 
extreme  right  controls  the  fast  and  slow  speeds  of 
the  cam  shaft. 

In  this  machine,  as  in  those  previously  described, 
the  axis  of  the  turret  is  vertical.  A  second  position 
is  possible — that  is,  the  axis  of  the  turret  may  be 
horizontal,  and  at  right  angles  to  the  line  of  the 
driving  spindle,  the  rotation  being  in  a  vertical  plane. 
This  position  is  utilized  in  the  Brown  &  Sharpe 
automatic  screw  machine,  shown  in  Figure  62.  This 
machine  is  fitted  with  a  motor  in  the  base,  driven  by 
a  short  belt  through  the  constant-speed  pulley  shown 
at  the  left  of  the  head-stock.  A  spring-actuated 
idler  pulley  near  the  motor  shaft  (not  shown)  main- 
tains the  proper  belt  tension.  In  this  machine  the 
cam  shaft,  controlling  the  motions,  is  in  front  of  the 
bed,  and  the  turret  is  at  the  forward  end  of  the 
turret  slide.  The  various  tools,  threading  dies,  and 
so  on,  are  arranged  around  the  face  of  the  turret  in 
the  six  positions,  and  are  held  in  place  by  bolts  which 
appear  on  the  front  face  of  the  turret. 

In  the  third  position  of  the  turret  the  axis  is  also 
horizontal,  but  is  parallel  with  the  axis  of  the  driving 


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FKIS.    ()1     AND    f)2.       AUTOMATIC    SCREW    MACIIINIIS 

Upikt:    llnrtfortl  Mathine  Screw  Co.     Lower:  IJrowh  ..V  Sluiri"' 
234  Mt>    Co. 


Tl  UU'KT   AM)   AlTo.MATh'   LATIIKS 


:!:;:> 


\v1iicli  (Mii;;i.i;('  a  pin  in  tlic  nicclianisin  al)()v<'.  Tho 
plate  under  llic  drivini;  pulleys  ()|)erates  tlie  l)elt- 
Nliirtini;  in<'clianisin  hy  means  oi'  the  (loii,'s  shown  on 
llie  edo-e.  The  tiniin.^'  ol*  the  helt-shii'lin.i;-  is  aceoni- 
|)lishe(l  by  slidin*;'  thes(»  dogs  to  the  ie(piired  position 
around  tlu*  edge  of  the  plat(^  The  next  earn  controls 
til*  motions  oi*  the  cuttiiig-olT  tool  located  in  the  sTuh' 
immc<liatelv  ahove  it.  The  lai'i;'e  cam  to  the  riiiht 
controls  the  motions  ot*  the  turret  cai'riage.  Tin* 
woivm  wheel  drives  the  cam  shaft,  and  the  plate  at  the 
(wtreme  i"iij;ht  controls  the  last  and  slow  speeds  ol* 
the  cam  shaft. 

In  this  machine,  as  in  those*  previously  <l(^scribed, 
the  axis  of  the  turret  is  veilical.     A  second   })osition 
is   possible — that   is,   the  axis   of  the   turret    may   he 
horizontal,    and    at    i'it;ht    angles    to    the    line    ol*    the 
dri\'iiii;-  spindle,  the  i-otation  heing  in  a  vei'tical  plane, 
'^riiis    position    is    utilized    in    the    Brown    «S:    Sharpe 
automatic  screw  machine,  shown  in  Figure  ()2.     This 
machine  is  litt(Nl  with  a  motoi'  in  the  base,  driven  by 
a  short  belt  through  tlu*  constant-speed  pulley  shown 
at    the    h4't    of    the    head-stock.     A    spring-actuat(Nl 
idler  pull(\v  near  the  motoi-  shaft   (not  shown)   main- 
tains  th(^   pi'op(M"   belt    tension.     In    this   machine   the 
'•am  shaft,  controlling  the  motions,  is  in  front  of  the 
bed,   and    the   turret    is   at    the    foi'wai'd    end    of   the 
'iirret   slide.     The  vai'ious   tools,  threa<ling  dii\s,  and 
o  (jn,  are  ananged  around  the  face  of  the  turret  in 
'lie  six  [jositions,  and  ar(»  held  in  place  by  bolts  which 
'|>pear  on  the  fi'ont    face  of  the  turret. 
Ill  the  third  position  of  the  turret  the  axis  is  also 
>rizontal.  but  is  parallel  with  the  axis  of  the  (h'i\in<» 


236  THE  MECHANICAL  EQUIPMENT 

spindle  instead  of  at  right  angles  to  it,  as  in  the 
Brown  &  Sharpe  machine.  An  example  of  this  is 
given  in  Figure  63,  which  shows  a  plan  view  of  the 
Cleveland  automatic  lathe,  in  which  the  turret  takes 
the  form  of  a  drum,  with  five  tool  positions  that 
rotate  in  a  plane  at  right  angles  to  the  axis  of  the 
machine.    The  cam  shaft  in  this  lathe  is  located  m 


'Chuck'closikA  riNacus 


FIG.   63.      TOP  VIEW  OF  A  CLEVELAND  AUTOMATIC  LATHE 

Cleveland  Automatic  Machine  Co. 

the  rear.  The  various  drums  are  clearly  shown. 
The  large  wheel  at  the  right  is  called  the  regulating 
wheel  and  carries  ten  segments,  two  for  each  hole  m 
the  turret,  which  can  be  adjusted  while  the  machine 
is  in  motion  to  suit  the  feed  requirements  of  each  of 
the  five  cutting  tools. 

Gridley*  Automatic  Lathe.— The  Gridley  automatic 
lathe,  shown  in  Figure  64,  another  horizontal  ma- 
chine,  represents  a  more  radical  departure  from  the 
old  standard  lathe  design.  The  long  bed  characteris- 
tic of  all  the  previous  machines  is  shortened  into  a 
more  or  less  box-like  frame,  and  the  turret,  instead  of 


riNarn  holder 

STOCK  VUSHCa  TUBE. 


FEED  SHAFT 
FTEO  nELEASiNO  LATC 


TUBNlW 

U  SLIOC 


Fi.ExiaLC  Oil  Tuae 


ORAW    BAR 


STOCK    FEED   CA 


FEED   CAM 
RETURN    CAM  ■ 


FEEO    CAvt    DRU 
CmuCK    OOERATINO    CAM^ 

HISH    SBEED    LEVER 

■  ELT   ShirreRs' 


TURRET    HtvOLV'^G    DOG 
'ORE'RATiNG    CA^4    DRUM 
BELT    SHIPPER    CAMS 


D    CUTTING    OFF.  CAM. DISC 

ORMING    SLIDE    CAK 
(CUTTING    OFF    CAM    ON 
OTHER  SIDE   OF   OlSC; 


II 


FIG.    64.      GRIDLEY    AUTOMATIC    LATHE — TURRET   WITH 


HORIZONTAL  AXIS 
Above:    Location  of  parts.    Below:    Sectional  view  through  the  tur- 
ret, showing  turret  supports  and  tool  slides.    The  National  Acme  Co. 

tmOt 


n 


O! 


230 


TUK  MKrilANHAl.  K(^ril*Mi:NT 


siMiullo  instcail  ol'  nt  ri-lit  angles  to  it,  as  Jii  tlio 
Brown  &  Sliai'pe  machine.  An  example  of  this  is 
oiv(^ii  in  Fiuure  (KJ,  which  shows  a  phm  view  ol'  tlie 
Clevehmd  automat ie  hithe,  in  which  the  tunvl  takes 
the  form  of  a  drum,  with  five  tool  positions  that 
rotate  in  a.  plane  at  right  angles  to  the  axis  of  the 
machine.     The  cam  shaft  in  this  lathe  is  located  in 


FIG.    63.      TOP   VIEW   or   A    CLKVKLANl)   AITOMATIC   LATHE 
ClevelaiKl  Automatic  Mucliine  Co. 

tlie  rear.  The  various  drums  are  clearly  sliown. 
Tlu»  large  wheel  at  the  right  is  called  the  regulating 
^vll('cl  and  carries  ten  segments,  two  for  each  hole  in 
the  turret,  which  can  he  adjusted  while  the  machine 
is  in  motion  to  suit  the  feed  requirements  of  each  of 
the  five  cutting  tools. 

Gridley  Automatic  Lathe— The  Gridley  automatic 
lathe,   shown   in  Figure   64,   another   horizontal  ma- 
chine, represents  a  more  radical  departure  from  thi 
old  standard  lathe  design.     The  long  bed  characteris 
tic  of  all  the  previous  machines  is  shortened  into  : 
more  or  less  box-like  frame,  and  the  turret,  instead  (- 


T*  ,^^i    Qf  f    ^..-.i    i;,, 


u  -  -  ■     _ 


FlC,.    ()4.      (iKlDLKV    AUTOMATIC    LATIIE — TURRET    WITH 

HORIZONTAL    AXIS 
\Im»v»':    Location  of  i)arts.     Below:    Sectional  view  Hinnmli  the  nir- 
n'l,  sliowiiit;-  lurrct  siippoiMs  ami  ♦ool  slides.     Tlie  National  Acme  To. 


238 


THE  MECHANICAL  EQUIPMENT 


being-  on  a  carriage  on  top  of  the  bed,  overhangs  at 
the  end.  The  various  tools  are  carried  on  the  faces  of 
the  turret,  and  the  feed  is  parallel  to  its  axis.  The 
cam  shaft  controlling  the  operations,  which  makes  the 
machine  automatic,  is  clearly  shown  in  the  frame 
below;  the  large  drum  at  the  left  controls  the  turret 
feeds  through  a  long  draw-bar  and  a  pin  which  en- 
gages the  cam  at  the  left.  The  cam  in  the  middle 
revolves  the  turret  and  operates  the  belt-shifting 
mechanism.  The  cam  at  the  right  operates  the  cross 
slide  and  cutting-off  tools. 

Multi-Spindle  Automatics.— The  longitudinal  posi- 
tion of  the  turret  axis  is  the  only  one  that  permits  of 
the  use  of  multiple  spindles.  This  fact  is  made  use 
of  in  the  Acme,  Gridley,  New  Britain,  and  other 
machines.  Figure  65  shows  a  multi-spindle  lathe  of 
this  type.  In  this  machine  an  indexing  head,  which 
corresponds  to  a  turret,  carries  six  spindles,  eacb  of 
which  may  contain  a  bar  stock  to  be  cut.  The  tool 
carriage  carries  an  equal  number  of  cutting  tools  in 
alignment  witb  each  of  these  revolving  shafts.  Each 
of  the  cutting  operations  has  an  independent  feed, 
controlled  by  the  operating  cams,  and  all  the  cutting 
tools  work  simultaneously.  The  cutting  tools  include 
the  cross-cut  tools  as  well  as  those  carried  in  the  main 
head.  When  the  longest  cut  is  finished,  the  tools  are 
withdrawn,  and  the  head  with  all  six  spindles  is  in- 
dexed around  to  the  next  position.    Then  the  process 

is  repeated. 

The  feeding  of  the  stock  is  done  at  one  of  the  posi- 
tions only,  at  each  indexing  of  the  turret.  This 
spindle  performs  the  first  operation,  the  other  opera- 


FIGS.   65  AND  66. 

Above:   Multi-spindle  Automatic  Lathe  for  Bar  Stock.  Below:  Mul- 
ti-spindle Automatic  Chucking  Lathe.    New  Britain  Machine  Co. 

239 


Till-:  MKciiANicAL  K(,)ri i\\ii:nt 


iM'iii-  oil  n  cai-ria.uc  on  lop  of  Ihc  Ixnl,  oviMliangs  at 
tlic  end.  I'lic  various  tools  aiv  carruHl  on  the  faces  of 
the  turret,  aiul  tiu'  feed  is  i)arallel  to  its  axis.  The 
cam  shaft  eontroUiui;-  the  operations,  vrhieh  makes  tlu^ 
uuu'hine  automatic,  is  clearly  shown  in  the  frame 
Ih'Iow;  tli(^  large  drum  at  the  left  controls  the  turret 
feeds  through  u  long  draw-har  and  a  ])in  which  en- 
gages the  cam  at  the  left.  The  cam  in  the  middle 
revolves  the  turret  and  o])erates  the  helt-shiftirig 
mechanism.  The  cam  at  the  right  operates  the  cross 
slide  and  cutting-off  tools. 

Multi-Spindle  Automatics.— The  longitudinal  po^  i- 
tion  of  the  turret  axis  is  the  only  one  that  permits  of 
tlie  nse  of  multiple  spindles.  This  fact  is  made  use 
of  in  the  Acme,  Gridley,  New  Britain,  and  other 
nuicliines.  Figure  05  shows  a  multi-spindle  lathe  of 
tliis  type.  In  this  machine  an  indexing  head,  Avliicli 
corresponds  to  a  turret,  carries  six  spindles,  each  of 
which  nuiy  contain  a  har  stock  to  he  cut.  The  tool 
earriage  carries  an  equal  numher  of  cutting  tools  in 
alignment  with  each  of  these  revolving  shafts.  Each 
of  the  cutting  operations  lias  an  independent  feisl, 
controlled  hy  the  operating  cams,  and  all  the  cuttin,';' 
tools  work  simultaneously.  The  cutting  tools  includ.^ 
tlie  cross-cut  tools  as  well  as  those  cari'ied  in  the  main 
head.  AVhen  the  longest  cut  is  finished,  the  tools  ar<' 
withdrawn,  and  the  head  with  all  six  spindles  is  in 
(U'xed  around  to  the  next  position.  Then  the  proces 
is  re])eated. 

The  feeding  of  the  stock  is  done  at  one  of  the  post 
tions  only,  at  each  indexing  of  the  turret.  Thi 
spindle  performs  the  tirst  operation,  the  other  oper;>- 


FIGS.    (io   AND   66. 

AIk)V(»:    ^IiiI11-si»iiHile  Autonintic  l.utlie  for  Bar  Stock.    Below:    Mill 
ti-spiiulle  AiitoiiijiJic  ( Miuckini:  Ljitlu'.     New  Britain  Msicliiiir-  Co. 


240 


THE  MECHANICAL  EQUIPMENT 


1 1 


III 


tioiis  are  performed  in  the  successive  positions,  and 
the  piece  is  completed  at  the  last.  A  piece  is  there- 
fore finished  on  the  last  spindle  at  each  indexing. 
As  many  operations  may  be  performed  as  there  are 
driving  spindles.  If  there  are  fewer  operations  than 
there  are  spindles  the  longest  operation  may  be  sub- 
divided, half  of  it  being  done  on  one  spindle  and  the 
remaining  half  on  the  next  one.  In  this  way,  the 
time  for  finishing  the  piece  may  be  materially  cut 
down.  This  type  of  machine  is  intended  for  bar- 
stock  work. 

The  machine  illustrated  in  Figure  66  shows  a  type 
designed  for  chucking  f orgings  and  castings,  in  which 
the  horizontal  turret  principle  is  used.  Here  the 
turret  is  carried  in  the  middle  on  a  long  shaft  that 
has  bearings  along  the  top  of  the  machine  and  rotates 
only.  There  are  two  spindle  heads,  one  on  each  side, 
each  with  three  working  spindles,  and  four  positions 
in  the  turret.  There  are  four  chucks,  which  corre- 
spond to  these  four  positions.  While  the  front  one  is 
being  filled,  work  is  going  on  on  each  side  of  the 
other  three  positions.  In  this  way  simultaneous 
machining  operations  may  be  performed  on  two  sides 
of  such  pieces  as  sprinkler  heads,  globe  valves,  and  so 
on.  This  not  only  saves  time,  but  saves  a  double 
chucking  of  the  piece — consequently  there  is  a  more 
accurate  alignment  of  the  two  cuts. 

Fay  Automatic  Lathe. — In  all  of  the  automatic 
lathes  described,  the  turret  principle  has  been  em- 
ployed in  some  form.  The  Fay  automatic  lathe, 
shown  in  Figure  67,  applies  the  automatic  principle 
and  cam  control  to  the  engine  type  of  lathe.    This 


li  I 


m 


FIGS.    67    AND    68.      ABOVE:     FAY    AUTOMATIC    LATHE 

BELOW:     LO-SWING    LATHE 

241 


--*'<■" 


240 


THE  .AIEnTANICAL  EQUIPMENT 


lions  arc  pcrroniicd  in  tlir  sncccssivc  |)()siiions,  and 
llic  piece  is  coniplcU'd  at  the  last.  A  piece  is  there- 
I'ore  linished  on  the  last  spindle  at  each  indexing. 
As  many  oi)erations  may  he  perrormod  as  there  are 
driving  spincUes.  It*  there  are  fewer  operations  than 
there  are  spindk's  the  longest  operation  may  be  sub- 
divided, half  of  it  being  done  on  one  spindle  and  the 
i-emaining  half  on  the  next  one.  In  this  way,  the 
time  for  finishing  the  piece  may  be  materially  cut 
down.  This  type  of  machine  is  intended  for  bar- 
stock  work. 

The  machine  illustrated  in  Figure  66  shows  a  type 
designed  for  chucking  forgings  and  castings,  in  which 
the  horizontal  turret  principle  is  used.  Here  the 
turret  is  carried  in  the  middle  on  a  long  shaft  that 
has  bearings  along  the  top  of  the  machine  and  rotates 
only.  There  are  two  spindle  heads,  one  on  each  side, 
eacii  with  three  working  spindles,  and  four  positions 
in  the  turret.  There  are  four  chucks,  which  corre- 
spond to  these  four  positions.  AVhile  the  front  one  is 
being  filled,  work  is  going  on  on  each  side  of  the 
otliei-  thi'ce  positions.  In  this  way  simultaneous 
machining  operations  may  be  performed  on  two  sides 
of  such  pieces  as  sprinkler  heads,  globe  valves,  and  so 
on.  This  not  only  saves  time,  but  saves  a  double 
cliucking  of  the  piece— consequently  there  is  a  more 
a:'curate  alignment  of  the  two  cuts. 

Fay  Automatic  Lathe. — In  all  of  the  automatic 
lathes  described,  the  turret  principle  has  been  em- 
ployed in  some  form.  The  Fay  automatic  latlus 
sliown  in  Figure  67,  applies  the  automatic  princi])!*' 
and  cam  control  to  the  engine  type  of  lathe.     This 


ri<JS.    ()7     AM)    (IS.       AMOVi::      FAV     AlTO.MAriC     I.ATIIE 

ni:u)\v  :    ia)-s\vl\<;   i.athi: 

LMl 


242 


THE  ME(  HANICAL  EQUIPMENT 


lathe  has  a  head-stock,  a  tail-stock,  and  a  carriage, 
but  they  are  modified  to  adapt  them  to  automatic 
operation.  It  is  intended  for  turning  work  which  is 
held  on  centers,  and  especially  for  that  class  that  is 
done  on  arbors,  where  the  cuts  are  to  be  concentric 
with  a  previously  finished  hole.  It  is  adapted  to  do 
straight,  taper,  and  formed  turning,  straight  and 
bevelled  facing,  and  recessing,  either  singly  or  in 
combination  with  roughing  or  finishing  cuts.  It  will 
not,  however,  do  threading  work,  for  which  it  is  not 
intended. 

The  spindle  of  this  lathe  is  a  large,  stiff,  iron  cast- 
ing running  in  iron-to-iron  bearings,  and  is  worm- 
driven.  This  locates  the  machine  drive  at  right 
angles  with  the  center  line  of  the  machine,  a  rather 
unusual  arrangement.  The  carriage,  instead  of 
sliding  on  V-ways  on  the  bed,  is  carried  on  a  heavy 
steel  bar  seated  in  the  head-  and  tail-stock  castings, 
which  ties  the  tool-supporting  and  work-supporting 
members  directly  together.  The  feeding  motion  in 
this  direction  is  governed  by  a  former  bar  secured  to 
the  front  of  the  bed.  As  the  carriage  feeds  over  this 
former  it  is  swung  up  or  down,  and  the  tools  are 
correspondingly  swung  toward,  or  away  from,  the 
work,  thus  controlling  the  contour  turned.  The  bar 
is  so  arranged  that  the  carriage  tools  are  swung  away 
from  the  work  in  returning  them  to  their  initial 
position  after  having  finished  a  cut. 

A  back  arm  is  provided  for  facing  cuts,  which  may 
be  made  while  turning  cuts  are  in  progress  with  the 
carriage  tools.  This  back  arm  is  pivoted  on  another 
bar,  which  is  also  supported  in  the  head-  and  tail- 


TURRET  AND  AUTOMATIC  LATHES 


243 


stocks.  It  is  swung  inward  by  a  heart  cam,  which  is 
geared  with  the  main  cam  drum.  This  arm  also 
carries  a  multiple  tool  block  of  the  same  construction 
as  that  used  on  the  carriage.  It  is  normally  used  for 
square  facing,  but  may  be  employed  for  recessing, 
bevel  facing,  and  for  taper  or  form  turning.  All  the 
movements  of  the  machine  are  controlled  by  cams. 

Lo-Swing  Lathe. — Figure  68  shows  a  special-pur- 
pose lathe,  for  heavy  production,  which  is  another 
modification  of  the  standard  engine  lathe.  This  lathe 
is  intended  to  turn  work  of  comparatively  small 
diameter  and  of  considerable  length,  which  must  be 
carried  on  centers.  The  face  plate  and  the  chuck  of 
the  ordinary  lathe  are  discarded.  The  swing  is  thus 
greatly  reduced,  and  at  the  same  time  the  chances  for 
springing  in  the  tool  carriage,  the  tail-stock,  and  so 
on,  are  lessened.  There  are  two  tool  carriages,  each 
capable  of  holding  several  tools,  so  arranged  as  to 
pass  by  the  tail-stock  for  starting  cuts  and  for  short 
work.  The  cross-section  of  the  bed  is  radically  dif- 
ferent from  that  of  an  ordinary  engine  lathe,  and  the 
carriage,  instead  of  sliding  on  V-ways  at  the  front  and 
back,  is  carried  on  a  strong,  narrow  guide  at  the  top 
and  front  of  the  bed.  The  tool-holder  is  a  low,  solid 
block,  resting  directly  on  the  carriage,  which  pro- 
vides an  exceptionally  rigid  support  for  the  cutting 
tools ;  there  is  only  one  joint  between  the  cutting  edge 
and 'the  bed.  A  taper  attachment  controlled  by  a  tem- 
plate furnishes  means  for  cutting  two  tapers  while 
other  cuts  are  in  progress.  One  or  both  of  the  car- 
riages may  be  used  and  each  carriage  may  have 
multiple-cutting  tools.    While  the  Lo-swing  lathe  has 


'.'Ml 


244 


THE  MECHANICAL  EQUIPMENT 


no  turret,  there  are  present  the  essential  features  of 
the  turret,  namely,  the  use  of  several  tools  and  the' 
preservation  of  the  adjustment  of  the  tools.  The  lathe 
is  especially  adapted  for  the  production  of  axles, 
spindles,  and  other  pieces  that  have  diameters  up  to 
314  inches  and  a  length  of  9  feet  or  under. 

Blanchard  Lathe. — Another  very  interesting  type  of 
automatic  lathe  is  known  as  the  Blanchard  lathe.  It 
is  named  after  its  inventor,  an  ingenious  old  New 
England  mechanic,  who  developed  the  lathe  for  the 
Springfield  Armory  in  1818,  to  be  used  in  turning  gun 
stocks.  In  this  type  the  work  is  rotated  at  a  moder- 
ate speed,  and  the  cutting  tool  has  an  independent 
rotation  of  its  own  like  that  of  a  milling  cutter  or  a 
saw.  This  cutting  tool  is  moved  in  and  out  from  the 
center  of  the  work  under  the  influence  of  a  former, 
which  rotates  at  the  same  speed  as  that  of  the  work. 
As  the  cutting  tool  travels  lengthwise,  it  can  be  made 
to  reproduce  accurately  very  irregular  shapes.  Two 
pieces  of  work  on  different  centers  may  be  made  to 
rotate  in  opposite  directions,  the  cutters  used  on  them 
being  operated  by  the  same  former.  This  will  cause 
the  former  to  reproduce  two  shapes,  which  will  be 
** right  and  left."  This  device  is  used  in  making  shoe 
lasts.  The  principle  involved,  in  addition  to  its 
original  purpose  of  turning  gun  stocks,  has  been  ap- 
plied in  an  endless  variety  of  uses,  from  manufactur- 
ing wheel  spokes  to  making  hobby-horse  heads:  A 
modern  form  of  this  lathe,  is  shown  in  Figure  170. 


CHAPTER  XV 
BOEING 

Wilkinson's  Boring  Machine.— The  boring  machine 
is  closely  allied  to  the  lathe.  Historically,  it  is  the 
oldest  of  the  modern  machine  tools.  The  boring 
machine  invented  by  John  Wilkinson,  of  Bersham, 
England,  in  1775,  made  Watt's  steam  engine  possible, 
Watt  invented  his  engine,  with  the  separate  con- 
denser, in  1765.  A  model  that  he  made  in  a  few  days 
clearly  demonstrated  the  correctness  of  its  principle, 
but  he  was  unable  for  ten  years  to  build  a  full-sized 
engine  that  could  be  a  commercial  success.  His 
trouble— the  inability  to  make  the  piston  steam- 
tight— was  due  to  the  impossibility,  at  that  time,  of 
boring  a  cylinder  round.  And  it  was  not  until  Wil- 
kinson built  a  boring  machine  with  a  boring  bar 
supported  on  each  side  of  the  work,  that  cylinders 
could  be  obtained  sufficiently  true  to  make  the 
engine  a  practical  possibility. 

From  that  time  on,  it  was  a  success.  Wilkinson's 
machine,  at  the  first  trial,  bored  a  cylinder  for  Watt 
57  inches  in  diameter  which  did  not  deviate  from 
truth  by  more  than  **the  thickness  of  an  old  shilling," 
possibly  a  little  more  than  1/32  of  an  inch.  This  was 
not  bad  work,  certainly  not  for  those  days,  and  Wil- 
kinson's machine  may  be  considered  as  the  first  of 

245 


\n 


'■  .(  H 


K 


246 


THE  MECHANICAL  EQUIPMENT 


the  modern  maxjhine  tools  for  anything  like  large 
work.  Maudslay's  slide  rest  and  improvements  in 
the  lathe  did  not  come  until  nearly  twenty-five  years 
later.  In  Wilkinson's  machine  the  cylinder  was 
strapped  to  heavy  oak  timbers.  A  large  cast-iron 
boring  bar  was  put  through  the  hole  and  carried  on 
trunions  which  were  mounted  on  the  timbers  at 
either  end  of  the  cylinder.  This  boring  bar  was 
rotated  by  power,  and  carried  a  cutting  tool  which 
was  fed  lengthwise  as  the  work  progressed.  His  ma- 
chine, therefore,  contained  the  essential  elements  of 
the  modern  horizontal  boring  machine. 

The  vertical  boring  mill  seems  to  have  been  first 
suggested  by  John  George  Bodmer,  a  Swiss  engineer 
who  lived  for  many  years  in  England.  He  described 
it  in  his  remarkable  patent  about  1840,  and  called  it  a 
** rotary  planer."  The  vertical  boring  mill  apparently 
made  very  little  impression  upon  English  mechanics 
at  that  time,  and  it  was  left  to  American  .tool  builders 
to  develop  this  type  of  machine  and  to  show  its  pos- 
sibilities. For  this  reason,  it  has  generally  been  con- 
sidered of.  American  origin,  although  there  is  little 
doubt  that  Bodmer 's  machine  antedates  the  use  of 
boring  mills  in  this  country. 

Boring  Mills  Classified. — The  term,  boring  mill,  is 
often  used  for  both  the  horizontal  and  the  vertical 
type.  This  usage,  however,  is  not  followed  by  tool 
builders,  who  confine  the  term  '* boring  mill"  to  the 
type  (usually  vertical)  in  which  the  work  revolves 
and  the  tool  is  stationary  except  for  the  feed.  The 
horizontal  type,  in  which  the  cutting  tool  revolves,  is 
termed  a  horizontal  boring  '* machine,"  the  essential 


BORING 


247 


idea  being  that  the  term  **miU"  is  confined  to  the 
cases  where  the  work  rotates. 

Machines  for  boring  range  in  size  from  those  that 
handle  work  12  or  14  inches  in  diameter,  to  those 
capable  of  turning  work  30  and  even  40  feet  in  diame- 
ter; the  latter  are  among  the  very  largest  machine 
tools  built.  This  wide  variety  of  machines  may  be 
roughly  classified  under  three  general  heads:  Vertical 
boring  mills,  horizontal  boring  machines  which  are 
self-contained,  and  portable  boring  machines  which 
are  used  in  floor-plate  work,  and  are  picked  up  by  a 
crane  and  moved  from  place  to  place,  as  they  are 
needed,  around  the  work. 

Vertical  Boring  Mill  versus  Lathe.— The  vertical 
boring  mill  is  adapted  to  boring,  turning,  and  facing 
cuts  that  are  concentric  with,  or  related  to,  a  single 
axis.  Reference  to  Figure  69,  and  also  to  Figure  71, 
will  show  that  it  is,  in  effect,  a  lathe  which  has  been 
stood  up  on  its  headstock  end,  and  that  its  principal 
elements  are  adaptations  of  lathe  parts,  the  tailstock 
being  omitted.  The  bed  of  the  machine,  a,  support- 
ing the  table  and  resting  upon  the  floor,  corresponds 
to  the  headstock;  the  rotating  table,  b,  to  the  lathe 
faceplace;  the  uprights,  c,  c,  to  the  lathe  bed;  the 
cross  rail,  d,  to  the  lathe  carriage.  The  tool-carrying 
head,  e,  is  an  elaborate  development  of  the  simple 
tool  post  of  the  engine  lathe.  The  machine  shown  in 
Figure  69  is  very  properly  termed  a  vertical  turret 
lathe,  since  the  turret  head  corresponds  closely  to 
the  turret  and  turret  slide  of  the  lathes  shown  in 
Figures  56  and  57,  and  the  side  tools  correspond  to 
the  cross-cutting  slide  shown  in  the  same  figures.     It 


248 


THE  MECHANICAL  EQUIPMENT 


FIG.   69.      VERTICAL  TURRET  LATHE 
Bullard  Machine  Tool  Co, 


BORING 


249 


contains  substantially  all  the  elements  of  these  ma- 
chines, modified,  of  course,  to  suit  their  position  and 
the  different  conditions  of  operation. 

The  vertical  position  characteristic  of  the  boring 
mill  gives  it  many  advantages  over  a  lathe  for  hand- 
ling short,  heavy  work  of  comparatively  large  diame- 
ter, such  as  pulleys,   gears,  flywheels,  pistons   and 
cylinder  heads,  car  wheels,  turbine  disks  and  casings, 
and  so  on.    In  the  first  place,  it  occupies  very  much 
less  floor  space  than  a  lathe  of  corresponding  size.    It 
would  be  difficult  to  secure  to  the  vertical  face  of  a 
lathe  faceplate  the  large  castings  handled  in  a  machine 
of  this  type.    It  would  be  difficult,  also,  to  balance  such 
pieces,  since  they  are  frequently  unsymmetrical;  and 
the    overhanging    weight    would    produce    a    heavy 
bending  strain  upon  a  lathe  spindle.    Pieces  of  this 
kind,  however,  may  be  set  by  a  crane  onto  the  table 
of  a  boring  mill  with  little  difficulty,  and  may  be 
easily  centered.    In  other  words,  *^it  is  easier  to  lay  a 
heavy  piece  down  than  to  hang  it  up."    Any  eccen- 
tricity of  weight  has  little  effect,  as  the  center  of 
gravity  is  almost  certain  to  fall  well  within  the  circle 
of  support.    The  very  weight  of  the  piece  is  a  help 
in  holding  it  to  a  boring-mill  table,  instead  of  being 
a  hindrance,  as  it  would  be  in  the  case  of  a  lathe 
faceplate. 

Vertical  Boring  MiU  versus  Planer.— Plain  facing 
work  may  be  done  on  a  vertical  boring  mill  or  on  a 
planer.  Eound  or  nearly  round  work  may  be  faced 
to  greater  advantage  on  a  boring  mill.  A  planer  cuts 
only  in  one  direction,  and  has  an  idle  return  stroke. 
It  therefore  works   at  a  disadvantage  on   cuts,   on 


I 


248 


THE  ME(  HANK^XL  EQUIPMENT 


FIG.    69.      VERTICAL   TURRET   LATHE 
Bullard  Mudiiue  Tool  Co, 


BORING 


249 


contains  substantially  all  the  elements  of  these  ma- 
chines, modified,  of  course,  to  suit  their  position  and 
the  different  conditions  of  operation. 

The  vertical  position  characteristic  of  the  boring 
mill  gives  it  many  advantages  over  a  lathe  for  hand- 
ling short,  heavy  work  of  comparatively  large  diame- 
ter,  such    as   pulleys,   gears,   flywheels,   pistons   and 
cylinder  heads,  car  wheels,  turbine  disks  and  casings, 
and  so  on.     In  the  first  place,  it  occupies  very  much 
less  floor  space  than  a  lathe  of  corresponding  size.    It 
would  be  difficult  to  s(U'ure  to  the  vertical  face  of  a 
lathe  faceplate  the  large  castings  handled  in  a  machine 
of  this  type.    It  would  be  difficult,  also,  to  balance  such 
pieces,  since  they  are  frequently  unsymmetrical;  and 
the    overhanging    weight    would    produce    a    heavy 
bending  strain  upon  a  lathe  spindle.     Pieces  of  this 
kind,  however,  may  be  set  by  a  crane  onto  the  table 
of  a   boring  mill   with   little  difficulty,   and   mav  be 
easily  centered.     In  other  words,  ^'it  is  easier  to  lay  a 
lieavy  piece  down  than  to  hang  it  up."     Any  eccen- 
tricity of  weight    has   little  effect,   as   the  center  of 
gravity  is  almost  certain  to  Fall  well  within  the  circle 
of  support.     The  very  wcMglit  of  the  i)iece  is  a  help 
in  holding  it  to  a  boring-mill  table,  instead  of  beini;- 
.1  hindrance,  as  it  would  be  in  the  case  of  a  lathe 
I'accplate. 

Vertical  Boring  Mill  versus  Planer.— Plain  facing 
work  may  be  done  on  a  vertical  boring  mill  or  on  a 
I>laner.  Round  oi-  nearly  round  work  may  be  faced 
t<)  greater  advantage  on  a  boring  mill.  A  planer  cuts 
only  in  one  direction,  and  has  an  idle  return  stroke. 
Tt  therefore    works   at   a   disadvantage   on    cuts,    on 


250 


THE  MECHANICAL  EQUIPMENT 


BORING 


251 


I 


y  MM 

ir 


which  a  boring  tool  could  be  working  continuously, 
or  nearly  so.  On  long,  narrow  faces  the  advantage 
is  reversed,  as  by  far  the  larger  part  of  the  time  a 
boring  mill  tool  would  be  making  its  slow  motion 
through  the  air,  and  much  more  time  would  be  lost 
than  would  be  the  case  with  the  quick  return  stroke 
of  the  planer.  The  reader  will  understand  this  more 
clearly  if  he  will  refer  to  Figure  70. 

A  flat  annular  surface,  such  as  the  flanged  end  of 
a  valve,  might  be  faced  on  a  planer  which  has  a 
stroke  equal  to  the  outside  diameter  and  a  side  feed 
of  the  same  amount.  The  cutting  tool,  in  covering 
the  square  indicated  at  A,  would  machine  the  sur- 


Cross  Feed  of  Planet'  Tool 


\Sfrolos  of 
FlaneK  Tool 


p'iS&^'ffe 


FIG.   70.      EFFECTIVE  CUTTING   AREAS  ON  THE  PLANER  AND 

BORING  MILL 


Pace,  but  it  would  do  useful  work  only  on  the  shaded 
portion,  a.  The  motion  of  the  tool  over  the  unshaded 
portions,  b,  b,  inside  and  out,  represents  lost  time.  If 
the  job  were  done  on  a  boring  mill,  the  tool  would  be 
set  at  the  outer  edge,  would  be  given  an  inward 
radial  feed,  represented  by  the  width  of  the  flange, 
and  the  work  would  be  rotated  under  the  tool,  as  in- 
dicated at  B.  In  this  case,  the  cutting  tool  would  be 
in  contact  with  the  work  all  the  time,  instead  of  only 
part  of  the  time,  and  the  length  of  feed  would  be  but 
a  small  fraction  of  that  required  in  the  first  case. 
The  advantage  is  therefore  clearly  with  the  boring 
mill. 

If,  however,  the  face  to  be  machined  is  long  and 
narrow,  as  at  C,  the  boring  mill  must  take  in  a  radius 
equal  to  the  distance,  c,  across  the  corners,  and 
the  tool  must  be  started  at  this  radius  and  fed  in 
to  the  center.  Not  until  it  has  reached  the  radius, 
d,  is  the  tool  in  the  work  during  the  entire  rotation, 
and  much  time  is  therefore  lost.  If,  on  the  other 
hand,  the  work  is  nearly  square,  as  shown  below  at 
D,  the  proportion  of  time  lost  between  the  radii,  c' 
and  d',  is  much  smaller,  and  the  gain  from  having  the 
tool  in  the  work  continuously  inside  the  radius,  d', 
may  render  it  desirable  to  do  the  work  on  a  boring 
mill. 

Construction  of  Vertical  Boring  Mill.— The  tools  in 
vertical  boring  mills  are  generally  carried  on  a  head 
which,  in  turn,  is  carried  on  a  cross  rail.  This  cross 
rail,  in  small  mills,  is  mounted  on  a  single  vertical 
support,  as  in  Figure  69,  of  box-like  cross  section, 
adapted  to  stand  the  combined  bending  and  torsional 


It"" 


PI 


252 


THE  MECHANICAL  EQUIPMENT 


i( 


strains  produced  by  the  cut.  In  all  except  the  smaller 
sizes  there  are  two  supports,  as  show  in  Figures  71 
and  72.  The  single  support,  or  upright,  is  used  on 
machines  that  table  up  to  about  42  inches  in  diame- 
ter. For  medium-sized  machines,  ranging  from  this 
size  up  to  15  to  20  feet  in  diameter,  there  are  two 
uprights  rigidly  bolted  to  the  bed  of  the  machine. 
For  large  mills,  the  two  uprights  are  sometimes  so 
arranged  that  they  may  be  slid  backward,  as  shown 
at  f,  Figure  71,  away  from  the  table,  so  that  the 
diameter  of  work  which  may  be  machined  is  thus  in- 
creased. Two,  or  even  three,  tool  posts  may  be 
carried  on  the  cross  rail;  and  in  small  sizes,  the  tool 
head  may  be  equipped  with  a  turret  and  used  in 
every  way  as  the  turret  might  be  on  a  heavy  turret 
chucking-lathe.  Such  a  turret  is  shown  at  g  in 
Figure  69.  The  heads,  e,  in  all  cases  swivel  about  a 
center,  may  be  adjusted  to  any  angle,  and  have  a 
power  feed  at  the  angle  so  set. 

For  straight  boring  or  turning,  the  head  remains 
stationary,  and  the  tool  post  or  turret,  as  the  case 
may  be,  is  fed  vertically  downward.  For  machining 
a  taper  surface,  the  head  is  set  at  the  required  angle 
and  the  tool  post  is  fed  in  that  direction.  In  this 
case,  as  in  the  previous  one,  the  head  would  be 
clamped  to  the  rail.  When  it  is  desired  to  machine  a 
flange  or  flat  face  at  right  angles  to  the  axis,  the 
tool  post  is  held  in  a  constant  position  in  the  head, 
and  the  whole  head  is  given  a  horizontal  side  feed 
along  the  rail.  In  certain  types  of  the  smaller  boring 
mills,  the  upright  is  equipped  with  an  auxiliary  side 
head,  h,  shown  in  Figure  69,  which  has  a  vertical 


1  .(in 


I 


i 


;  M 


Aia^  ^^^*   ^^  ^^^  ^^'      VERTICAL  BORING  MILLS 

16-foot  mUl  -^t^^^^^^^^^^^^  above;  a  34-foot  mil,,  below, 

uotn  built  by  Niles-Bement-Pond  Co. 

253 


252 


THE  MEtllAiNKAl.  Hi^lll^MEiNT 


strains  produced  by  the  cut.  Jn  all  except  tlie  smaller 
sizes  there  are  two  supports,  as  show  in  Figures  71 
and  72.  The  single  suppoi't,  or  upright,  is  used  on 
machines  that  table  up  to  about  42  inches  in  diame- 
ter. For  medium-sized  machines,  ranging  from  this 
size  up  to  IT)  to  2i)  feet  in  diameter,  there  are  two 
uprights  rigidly  bolted  to  the  bed  of  the  machine. 
For  large  mills,  the  two  uprights  are  sometimes  so 
arranged  that  thev  mav  be  slid  backward,  as  shown 
at  f,  Figure  71,  away  from  the  table,  so  that  the 
diameter  of  work  which  may  l)e  machined  is  thus  in- 
creased. Two,  or  even  three,  tool  posts  may  i)e 
carried  on  the  cross  rail;  and  in  small  sizes,  the  tool 
head  may  be  equipped  with  a  turret  and  used  in 
every  way  as  the  tui-ret  inight  be  on  a  heavy  turrc^t 
chucking-lathe.  Such  a  turret  is  shown  at  g  in 
Figure  69.  The  heads,  e,  in  all  cases  swivel  about  n 
center,  may  be  adjusted  to  any  angle,  and  have  a 
power  feed  at  the  angle  so  set. 

For  straight  boring  or  turning,  the  head  remains 
stationary,  and  the  tool  post  or  turret,  as  the  case 
mav  be,  is  fed  verticallv  downward.  For  machinin.u 
a  taper  surface,  tlu^  head  is  st^t  at  the  required  angle 
and  the  tool  post  is  fed  in  that  direction.  In  this 
case,  as  in  the  previous  one,  the  head  would  1h' 
clamped  to  the  rail.  When  it  is  desired  to  machine  n 
flange  or  flat  face  at  right  angles  to  the  axis,  Hk' 
tool  post  is  held  in  a  eonstant  position  in  the  head 
and  the  whole  hea<[  is  given  a  hoi-i/onlal  side  Tefl 
along  the  rail.  In  certain  lyjies  ol*  the  smaller  borii  ,: 
mills,  the  upright  is  ('([uipped  with  an  auxiliary  si-i-' 
head,   h,   shown   in   Figure   (J!),   wliieh    has   a   vertierJ 


^^^^'   ^^   ^^^   '^--      ^'^'RTICAL  BORING    MILLS 
ISotli  built   by  Nilos-lJeiiieni-INMul  ( \> 


LM3 


254 


THE  MECHANICAL  EQUIPMENT 


feed  np  and  down  the  face  of  the  work  and  a  hori- 
zontal feed  toward  the  center.  This  head,  also,  may 
carry  a  turret  tool  holder,  h',  and  the  tools  may  work 
simultaneously  with  those  in  the  head  carried  on  the 
cross  rail.  In  this  respect,  again,  the  boring  mill 
corresponds  closely  to  the  turret  lathes  referred  to  in 
Figures  56  and  57. 

When  two  heads  are  carried  on  the  cross  rail,  they 
are  provided  with  independent  feeds  in  all  direc- 
tions, in  order  that  they  may  work  simultaneously, 
and  independently  of  each  other.  As  the  weight  of 
the  cross  rail  and  heads  is  considerable,  they  are 
counterbalanced  by  weights,  shown  in  Figure  71.  In 
boring  mills  with  the  adjustable  uprights,  the  latter 
are  set  well  back,  and  the  usual  type  of  tool  head, 
shown  to  the  right  in  Figure  71,  would  not  reach  in 
close  enough  to  the  center  to  work  on  small  diame- 
ters. This  difficulty  is  met  by  mounting  one  of  the 
tool  heads  on  an  extension,  i,  which  reaches  forward 
toward  the  center,  enabling  that  head  to  machine  the 
small  diameters.  The  feeds  of  the  cross  rail  on  the 
uprights,  the  tool  heads  on  the  cross  rail,  the  slides 
in  the  tool  heads,  as  well  as  the  feeds  in  the  side  head, 
if  there  are  any,  are  all  power-driven. 

In  the  early  history  of  the  boring  mill,  al- 
though its  great  capacity  for  removing  metal  was 
clearly  recognized,  it  was  considered  only  as  a 
roughing  tool  and  accurate  work  was  performed  upon 
a  large  engine  lathe.  Of  late  years,  however,  the  de- 
sign and  construction  of  the  boring  mill  have  been 
so  refined  and  developed  that  it  has  almost  com- 
pletely taken  over  work  of  this  character.    This  is 


BORING 


255 


especially  true  in  the  case  of  the  vertical  turret 
machines,  which  have  come  into  very  wide  use  for 
such  work  in  connection  with  car  wheels,  gears,  and 
so  on. 

Table,  Drive  and  Tools.— The  revolving  table  in  a 
boring  mill  is  the  important  factor  upon  which  ac- 
curacy and  quality  of  the  work  depends.    It  should 
be  very  rigid,  and  capable  of  revolving  smoothly  at 
high  speeds  under  heavy  cuts.     The  spindle  under- 
neath, which  corresponds  to  the  spindle  of  the  lathe, 
is  a  sufficient  support  for  the  smaller  sizes.    In  all 
medium  and  larger  sizes  the  spindle  is  relied  on  to 
do  the  centering  only,  and  the  weight  and  the  vertical 
tool  thrust  are  carried  on  a  circular  bearing  of  larger 
diameter,  which  usually  is  slightly  conical  so  that  it 
will  be  self-centering  as  it  wears.     The  table  is  driven 
from  a  point  near  the  rim,  located  as  nearly  under  the 
cutting  tool  as  possible  to  eliminate  torsion  on  the 
spindle. 

The  bevel  gear  form  of  drive  is  most  used,  but  it 
has  some  disadvantages,  since  it  has  a  slight  tendency 
to  lift  the  table.  To  obviate  this,  worm  gearing  is 
used  in  some  cases,  as  its  action  is  smoother  and 
more  continuous  than  that  of  either  spur  or  bevel 
gearing.  For  heavy  work  the  worm  gear  is  not 
available,  on  account  of  its  low  efficiency  and  heavy 
end  pressure.  Large  boring  mills  are  therefore  driven 
by  spur  or  bevel  gearing;  spur  gearing  is  used  on 
the  largest  types  of  machines,  as  shown  at  i  in  Fig- 
ure 71.  ^ 

The  cutting  tools  used  in  these  machines  may  be 
(^ither  of  the  type  used  on  a  heavy  planer  or  of  the 


256 


THE  MECHANICAL  EQUIPMENT 


kind  used  in  a  large  turret  chucking  lathe.  The 
pilot  bar  principle,  described  in  the  last  chapter,  is 
made  use  of  on  the  boring  mill  as  well.  The  vertical 
boring  mill,  in  its  larger  sizes,  is  used  for  work  of  a 
varied  nature,  ranging  from  general  jobbing  work  to 
the  machining  of  large  castings  incident  to  building 
heavy  machinery  of  all  kinds.  The  smaller  sizes, 
with  special  tool  equipment,  are  used  for  accurate 
repetition  work  on  a  strictly  manufacturing  basis. 
They  are  well  adapted  for  this,  since,  because  they 
require  little  floor  space,  the  work  may  be  set  in 
position  easily  and  quickly,  and  the  machine  will  take 
heavy  and  simultaneous  cuts  with  all  the  accuracy 
required  in  this  type  of  work. 

Bullard  Mult-au-matic  Vertical  Lathe. — Figure  73 
shows  the  Bullard  Mult-au-matic  vertical  lathe,  a  de- 
velopment from  the  small  boring  mill  shown  in 
Figure  69.  It  is,  in  effect,  five  automatic  chucking 
lathes  arranged  vertically  around  one  bed,  in  a  space 
6  feet  in  diameter  and  12  feet  3  inches  high,  including 
the  motor.  There  are  5  tool  heads,  which  will  face, 
bore,  and  turn  at  any  angle  independently  of  one 
another;  and  6  independently  rotating  chucks  or 
tables,  14  inches  in  diameter,  are  carried  on  an  in- 
dexing, circular  base.  Five  of  the  chucks  revolve 
under  the  tool  heads — the  sixth  is  at  the  loading  posi- 
tion or  station  at  rest.  While  a  new  piece  is  being  set 
in  this  chuck,  all  of  the  others  are  working.  When  a 
new  piece  is  in  place,  the  circular  base  is  indexed  one 
station  and  each  piece  comes  under  the  next  tool  head; 
the  last  comes  to  the  loading  station,  finished  and  ready 
to  be  taken  out.    The  next  piece  is  then  sent  on  its 


no.  73. 


** MULT-AU-MATIC*'  VERTICAL  LATHE 
Bullard  Machine  Tool  C!o. 
257 


tw 


25G 


'p 


THE  MECHAXICAL  EQl  IPMENT 


kind  used  in  a  largo  turret  chucking  latlie.  The 
pilot  bar  principle,  described  in  the  last  chapter,  is 
made  use  of  on  the  boring  mill  as  well.  The  vertical 
boring  mill,  in  its  larger  sizes,  is  used  for  work  of  a 
varied  nature,  ranging  from  gcMiei-al  jobbing  work  to 
the  machining  of  large  castings  incident  to  building 
heavy  machinery  of  all  kinds.  The  smaller  sizes, 
with  special  tool  equipment,  are  used  for  accurate 
repetition  work  on  a  strictly  manufacturing  basis. 
They  are  well  adapted  for  this,  since,  because  they 
require  little  floor  space,  the  work  may  be  set  in 
position  easily  and  quickly,  and  the  machine  will  take 
heavy  and  simultaneous  cuts  with  all  the  accuracy 
required  in  this  type  of  work. 

BuUard  Mult-au-matic  Vertical  Lathe.— Figure  73 
shows  the  Bullard  Mult-au-matic  vertical  lathe,  a  de- 
velopment from  the  small  boring  mill  shown  in 
Figure  69.  It  is,  in  effect,  five  automatic  chucking 
lathes  arranged  vertically  around  one  bed,  in  a  space 
6  feet  in  diameter  and  12  feet  3  inches  high,  including 
the  motor.  There  are  T)  tool  heads,  which  will  t'ac(\ 
bore,  and  turn  at  any  angle  independently  of  on<' 
another;  and  6  independently  rotating  chucks  or 
tables,  14  inches  in  diameter,  are  carried  on  an  in- 
dexing, circular  base.  Five  of  the  chucks  revolve- 
under  the  tool  heads — the  sixth  is  at  the  loading  posi- 
tion or  station  at  rest.  While  a  new  piece  is  being  set 
in  this  chuck,  all  of  the  others  are  working.  When  u 
new  piece  is  in  place,  the  circular  base  is  indexed  one 
station  and  each  piece  comes  under  the  next  tool  head: 
the  last  comes  to  the  loading  station,  linished  and  read; 
to  be  taken  out.     The  next  piece  is  then  sent  on  i*^ 


V. 


FIG.    73.      **MILT-Al-MATIC"    VERTICAL   LATHE 
Bullanl  Mnoliine  Tool   Co. 


257 


258 


THE  MECHANICAL  EQUIPMENT 


way  around.  This  method  is  an  application  of  the 
** station''  principle  used  in  the  multi-spindle  lathes 
described  in  Chapter  XIV.  The  indexing,  fast  and 
slow  feeds  of  all  the  tool  heads,  both  forward  and 
return,  are  entirely  automatic.  This  machine  reduced 
the  time  of  finishing  a  fly  wheel  on  the  Ford  motor 
from  thirty-two  minutes  to  fifty  seconds. 

Horizontal  Boring  Machine.— As  there  is  an 
analogy  between  the  vertical  boring  mill  and  the  lathe 
with  the  work  bolted  to  the  faceplate,  so  the  horizon- 
tal boring  machine  may  be  likened  to  a  lathe  with 
the  work  bolted  to  the  carriage.  There  is,  however, 
a  fundamental  difference  between  these  arrange- 
ments, since  in  one  case  the  work  revolves  against 
the  tool,  and  in  the  other  the  tool  moves  against  the 
work.  It  will  be  found  that  there  is  a  similar  dif- 
ference between  the  planer  and  the  shaper.  Which  of 
these  methods  is  the  better,  depends  upon  the  size 
and  shape  of  the  piece,  and  of  the  cut  in  relation  to  the 
piece.  The  feasibility  of  revolving  the  work  in  an 
operation  like  that  of  turning  a  carwheel,  is  evident. 
It  is  equally  clear  that  it  would  be  disadvantageous 
to  revolve  a  large  engine  bed  around  the  center  line 
of  the  main  shaft  bearing,  merely  to  bore  out  that 
bearing.  The  swing  required  would  be  enormous  and 
would  call  for  a  boring  mill  utterly  disproportionate 
to  the  size  of  the  cut  to  be  made.  With  such  a  piece 
as  this,  it  is  obviously  better  to  clamp  the  casting 
firmly  on  a  base,  place  a  boring  bar  on  the  center 
line  of  the  shaft,  and  bore  the  bearing  by  revolving 
a  tool  carried  by  the  bar. 

Unlike    the    vertical    boring    mill,    the    horizontal 


BORING 


259 


boring  machine  offers  a  means  of  machining  con- 
veniently and  accurately  surfaces  which  are  related 
to  several  axes;  these  axes  may  be  either  parallel,  at 
right  angles,  or  even  at  an  odd  angle.  A  case  in 
point  is  the  machining  of  the  main  cylinder  bore  and 
the  holes  for  the  steam  and  exhaust  valve  in  a  Corliss 
engine  cylinder.  The  latter  holes — four  in  number — 
are  parallel  to  one  another,  and  at  right  angles  to 
the  main  cylinder  bore.  The  casting  may  be  mounted 
on  the  table  of  a  horizontal  boring  machine — like 
those  in  Figures  74  to  77 — the  cylinder  hole  bored, 
and  the  end  flanges  faced.  The  table,  with  the 
cylinder  still  clamped  to  it,  may  then  be  indexed 
through  90  degrees. 

By  operating  the  traverses  of  the  table  and  the 
head  spindle,  the  spindle  may  be  brought  opposite 
one  of  the  valve  holes,  and  that  may  be  bored  and  its 
end  flanges  may  be  faced.  The  spindle  center  may 
then  be  shifted  to  coincide  with  each  of  the  other 
three  valve  hole  centers,  and  these  may  be  finished 
successively  as  the  first  one  was.  All  these  opera- 
tions may  be  finished,  within  the  limits  of  accuracy 
of  the  adjustments  of  the  machine,  with  a  single 
clamping  of  the  work  upon  the  table.  Thus  it  is 
possible  to  avoid  the  loss  of  time  and  the  chances  of 
error  involved  in  shifting  the  work  and  making  a 
series  of  set-ups.  The  horizontal  type  of  machine  is 
better  for  boring  holes  which  are  long  in  proportion 
to  their  diameter.  This  advantage  comes  from  the 
use  of  the  outboard  bearing  or  tail-block  which  sup- 
ports the  boring  bar  at  the  farther  end,  as  shown  in 
Figure  75. 


260 


THE  MECHANICAL  EQUIPMENT 


Similarity  to  the  Lathe.— The  horizontal  type  of 
machine  is  more  closely  similar,  in  general  design,  to 
the  lathe  than  is  the  vertical  boring  mill.     This  is 
especially  true  of  the  machines  which  have  stationary 
spindles  and  elevating  tables,  as  in  the  Niles-Bement- 
Pond  machine,  Figure  74.    The  boring  head  is  similar 
in  position  and  general  design  to  the  headstock  of  the 
engine  lathe,   the   essential  difference  being  a  pro- 
vision for  the  horizontal  feed  of  the  spindle.    This 
provision  is  usually  made  by  having  a  hollow  rotat- 
ing spindle,  b,  without  lateral  motion,  and  an  inner 
spindle,  c,  sliding  longitudinally  through  this  outer 
one,  which  is  provided  with  an  independent  traverse 
feed.    In  machines  of  this  type  the  table  and  platen, 
a,  are  carried  on  elevating  screws,  d,  which  afford  a 
vertical  adjustment  for  the  adaptation  of  the  table  to 
various  types  of  work.     The  outboard  bearing,  e,  is 
carried  in  a  stationary  yoke,  f,  which  corresponds  to 
the    tailstock    of   the    engine    lathe.    This    outboard 
bearing  is  used  in  boring  long  holes,  or  wherever 
support  for  the  spindle  is  needed,  and  the  yoke  serves 
as  a  support  to  which  the  table  may  be  clamped  when 
it  has  been  brought  to  the  desired  position. 

An  Adaptable  Type.— Another  widely  used  type  is 
shown  in  Figure  75.  In  this  machine,  built  by  the 
Lucas  Machine  Tool  Co.,  variation  in  height  between 
spindle  and  table  is  obtained  by  adjusting  the  height 
of  the  boring  head,  a,  instead  of  that  of  the  table.  The 
bed  of  the  machine  is  of  rectangular  box  section,  and 
the  boring  head  is  carried  on  a  heavy  column  at  the 
left  end  of  the  machine;  the  head  is  adjustable  verti- 
cally on  suitable  gibbed  slideways,  b.    A  stiff  back 


'    ,' 


1. 1 


FIGS.  74  AND  75.      HORIZONTAL  BORING  MACHINES  2eX 


260 


THE  MECHANICAL   i:(^CJPMi:\T 


Similarity  to  the  Lathe.— The  horizontal  typo  of 
machine  is  more  closely  similar,  in  general  design,  to 
the  lathe  than  is  the  vertical  horini;'  mill.  This  is 
especially  true  of  the  machines  which  have  stationarv 

« 

spindles  and  elevating  tables,  as  in  the  Xiles-P>ement- 
Pond  machine,  Figure  74.    The  boring  head  is  similar 
in  position  and  general  design  to  the  headstock  of  the 
engine    lathe,   the    essential    dilTerence    being    a    pro- 
vision for  the  horizontal  feed   of  the   spindle.     This 
provision  is  usually  made  by  having  a  h'jllow  rotat- 
ing spindle,  b,  without   lateral   motion,  and  an   inner 
spindle,  e,  sliding  longitudinally  through   this  outer 
one,  which  is  provided  with  an  independent  traverse 
feed.     In  machines  of  this  type  the  table  and  platen, 
a,  are  carried  on  elevating  screws,  d,  which  afford  a 
vertical  adjustment  for  the  adaptation  of  the  table  to 
various  types  of  work.     The  outl)oard   bearing,  e,   is 
carried  in  a  stationary  yoke,  f,  vMch  corresi)onds  to 
the    tailstock    of    the    engine    lathe.     This    outboard 
bearing   is   used    in    boring   long   holes,   or   wluM-ever 
support  for  the  s])indle  is  needed,  and  tlie  yoke  serves 
as  a  support  to  which  the  table  may  be  cbimi)ed  when 
it  has  been  brought  to  the  desired  position. 

An  Adaptable  Type.— Another  widely  used  type  is 
shown  in  Figure  7.').  In  this  machine,  built  bv  the 
Lucas  Machine  Tool  Co.,  variation  in  height  between 
spindle  and  table  is  obtained  by  adjusting  the  height 
of  the  boring  head,  a,  instead  of  that  of  the  table.  The 
bed  of  the  machine  is  of  rectangulai*  box  section,  and 
the  boring  head  is  carried  on  a  heavy  column  at  tlir 
left  end  of  the  machine;  the  head  is  adjustable  verti 
eally  on  suitable  gibbed  slide  ways,  b.     A  stiff  back 


•^■'^■jf'- 


FKiS.   74   AND  75.      IIOKIZOXTAL  BORING   MACHINES 


201 


262 


THE  MECHANICAL  EQUIPMENT 


BORING 


263 


i 


rest,  c,  at  the  right  end  of  the  machine  has  slide- 
ways  for  a  tail-block,  d,  which  is  fed  up  and  down  in 
conjunction  with  the  main  boring  head;  the  proper 
alignment  with  the  spindle  is  maintained  by  feed 
screws  operated  through  bevel  gears  from  a  common 
shaft.  After  the  tail-block  is  in  position,  it  may  be 
locked  in  place,  when  it  becomes  practically  of  one 
piece  with  the  back  rest.  The  back  rest,  c,  is  ad- 
justable forward  and  backward,  so  that  it  will  accom- 
modate work  of  various  lengths,  or  it  may  be  removed 
from  the  bed  without  disturbing  any  of  the  other 
mechanism.  The  main  spindle  is  driven  through  back 
gears  in  the  head,  which  are  engaged  and  disengaged 
by  convenient  interlocking  levers.  The  platen,  e,  is 
furnished  with  T-slots  and  with  a  circular  swiveling 
table,  not  shown.  It  slides  transversely  on  the 
saddle,  f,  which  in  turn  slides  lengthwise  of  the 
machine. 

Power  feeds  are  provided  for  the  spindlo  in  and 
out,  the  spindle  and  tail-block  up  and  down,  the  saddle 
along  the  bed,  and  the  platen  across  the  saddle. 
Reverse  feeds,  rapid  traverse,  and  hand  adjustments 
are  provided  for  all  feeds.  The  machine  has  a  con- 
stant-speed drive,  which  may  be  operated  by  either 
belt  or  motor,  the  variations  in  spindle  speed  being 
made  through  change  gears  operated  by  the  levers 
at  the  front  of  the  bed.  This  type  of  machine  is 
useful  for  many  kinds  of  boring,  drilling,  and  milling 
operations.  For  drilling,  the  tool  is  mounted  directly 
in  the  head  spindle,  g,  and  the  platen  is  brought  close 
to  the  spindle  head.  This  position  may  also  be  used 
for  milling  operations;  the  milling  cutter  is  mounted 


on  the  end  of  the  spindle  or  carried  on  an  arbor 
between  the  head,  a,  and  tail-block,  d.  For  boring 
long  holes,  the  tail-block  and  the  back  rest  are  used, 
the  spindle  is  extended  to  run  through  the  tail-block, 
and  the  cutting  tool  is  mounted  on  the  spindle,  which 
is  rotated  and  fed  forward  at  the  same  time.  For 
vertical  milling  work,  an  attachment  is  provided, 
which  IS  shown  in  Figure  76.  This  consists  of  a 
heavy  cast  iron  yoke,  h,  which  spans  the  opening 
between  the  spindle  head,  a,  and  the  tailblock,  d,  and 
is  firmly  bolted  to  each.  On  this  yoke  is  mounted 
a  traveling  head,  i,  carrying  a  vertical  spindle  driven 
from  the  main  spindle  through  bevel  gears.  A  face 
milling  cutter,  j,  may  be  mounted  on  the  lower  end 
of  this  spindle,  and  the  machine  may  be  used  to  do 
vertical  milling  operations.  In  the  latest  type  of 
Bement  boring  machine,  all  the  operating  levers  are 
arranged  in  pairs,  one  on  each  side  of  the  machine,  so 
that  it  may  be  controlled  from  whichever  side  happens 
to  be  most  convenient.  Figure  77  shows  a  much  larger 
machine  of  the  same  general  type. 

Portable  Boring  Machines. — In  very  heavy  ma- 
chinery— as,  for  instance,  rolling  mill  engines — some 
of  the  parts  to  be  machined  are  of  very  great  size  and 
weight.  In  machining  such  pieces,  it  would  be  ex- 
pensive and  inconvenient  to  shift  their  positions  to 
make  the  various  cuts  required.  It  is  simpler  and 
easier  to  move  the  machines  around  the  castings. 
Shops  equipped  for  work  of  this  magnitude  are  pro- 
vided with  slotted  floor  plates,  which  are  located  in 
the  main  bay  of  a  building  of  the  type  shown  in 
Figure  1,  under  the  large  traveling  crane. 


•1 


BORING 


265 


FIGS.  76  AND  77.      HORIZONTAL  BORING   MACHINES 
The  Tipper,  Fig.  76,  is  shown  with  vertical  milling  attachment   and 
is  built  by  Lucas  Machine  Tool  Co.     The  lower  machine  is  built 

by  Niles-Bement-Pond  Co. 
264 


These  plates  are  built  up  of  sections,  and  may  cover 
a  considerable  portion  of  the  floor.  Their  upper  sur- 
face is  machined  and  is  provided  with  T-slots.  They 
are  firmly  bedded  in  a  heavy  concrete  foundation 
and,  when  finished,  correspond,  except  for  their  much 
greater  size,  to  the  base  plate,  a,  shown  in  Figure  77. 
The  large  casting  to  be  machined  is  brought  in  from 
the  foundry,  leveled,  and  clamped  in  place  upon  this 
floor  plate;  it  is  not  moved  until  all  the  machine  work 
is  done.  When  boring  operations  are  necessary,  a 
portable  boring  mill— corresponding  to  the  vertical 
portion  of  the  mill  shown  in  Figure  77— is  placed  in 
position  on  the  floor  plate  beside  the  casting,  is 
clamped  into  place,  and  the  operations  called  for  at 
that  location  are  performed. 

When  it  is  necessary  to  move  the  machine  to  some 
other  part  of  the  casting,  the  crane  hook  is  slipped 
into  a  heavy  loop,  or  bail,  at  the  top  of  the  machine, 
and  it  is  lifted  bodily,  turned  around,  and  transported 
as  may  be  necessary.  It  is  set  in  its  new  location, 
and  the  slots  in  the  floor  plate  are  used  to  orient  the 
machine  in  proper  position.  The  same  thing  is  done 
with  other  types  of  machines,  such  as  large  draw-cut 
shapers,  and  so  on.  Whether  it  is  desirable  to  move 
the  machine  around  the  work  or  the  work  around  the 
machine,  is  largely  a  question  of  the  relative  size  of 
the  two;  when  the  work  is  of  very  great  size,  the 
former  method  is  the  cheaper.  Portable  boring  ma- 
chines of  this  type  are  invariably  motor-driven,  the 
motor  being  mounted  on  the  machine  itself  and  trans- 
ported with  it. 


!',    tl 


0j 


FIGS.   7()    AND   77.       HORIZONTAL  BOKIXO    MACHINES 

The  upper,  Fi.?.  7G,  is  sliown  with  vertical  niilllng  attaclimont    an' 
IS  biiiU  by  Lucas  :Ma('hine  Tool   To.     The  lower  machine  is  buii 

l>.v  NiIes-P,«»nuMit-ron(i  Co, 
204 


BORING 


265 


Those  platos  are  huUi  up  of  sections,  and  may  cover 
a  consi(l(M-al)le  portion  of  the  th)or.  Their  ii{)per  sur- 
face is  macliined  and  is  jn-ovided  witli  T-sh)ts.  They 
ai-e  firmly  hedchnl  in  a  heavy  concrete  foun(hition 
and,  \vh(^n  finislied,  correspond,  except  for  their  much 
greater  size,  to  the  ])ase  pkite,  a,  shown  in  Figure  77. 
The  hirge  casting  to  be  macliined  is  brought  in  from 
the  foundry,  leveled,  and  clamped  in  i)lace  upon  this 
floor  plate;  it  is  not  moved  until  all  the  machine  work 
is  done.  AVlien  boring  operations  are  necessary,  a 
portable  boring  mill — corresponding  to  the  vertical 
])ortion  of  the  mill  shown  in  P'igure  77— is  ])laced  in 
position  on  the  lloor  plate  ])eside  the  casting,  is 
clamijcd  into  place,  and  the  operations  called  for  at 
that  location  are  performed. 

When  it  is  necessary  to  move  the  machine  to  some 
other  part  of  the  casting,  the  crane  hook  is  slipped 
into  a  heavy  loop,  or  bail,  at  the  top  of  the  machine, 
and  it  is  lifted  l)odily,  turned  around,  and  transported 
as  may  be  necessary.  It  is  set  in  its  new  location, 
and  the  slots  in  the  floor  plate  are  used  to  orient  the 
machine  in  proper  position.  The  same  thing  is  done 
with  other  types  of  machines,  such  as  large  draw-cut 
shapers,  and  so  on.  Whether  it  is  desirable  to  move 
the  machine  around  the  work  or  the  work  around  the 
machine,  is  largely  a  question  of  the  relative  size  of 
the  two;  when  the  work  is  of  very  great  size,  the 
iormer  method  is  the  cheaper.  Portable  boring  ma- 
fliines  of  this  type  are  invariably  motor-driven,  the 
motor  being  mounted  on  the  machine  itself  and  trans- 
ported with  it. 


Ii 


CHAPTER  XVI 
DEILLING  MACHINEKY 

The  Sensitive  Drill. — Drilling  machines,  in  some 
form,  are  found  in  every  shop.  They  are  used  for 
drilling  round  holes  in  all  kinds  of  castings  and 
forgings;  for  tapping  or  threading  the  holes;  for 
countersinking  or  making  a  tapered  enlargement  of  the 
upper  end  of  a  hole;  for  counterboring  or  making  an 
annular  enlargement  of  the  upper  end  of  a  hole;  for 
reaming,  which  is  passing  a  reamer  through  the  hole 
to  increase  the  accuracy  of  form ;  and  for  spot  facing, 
which  is  making  a  shallow  counterbore  deep  enough 
to  form  a  smooth  face  for  the  head  or  nut  of  a  bolt. 

The  smallest  and  simplest  form  is  a  sensitive  drill, 
Figure  78.  It  consists  of  an  upright  standard,  a 
smooth  horizontal  table  on  which  to  rest  the  work, 
a  vertical  spindle  capable  of  holding  and  rotating  the 
drill,  and  means  for  feeding  either  the  work  or  the 
drill,  usually  the  latter.  The  variations  in  speed  are 
generally  obtained  by  means  of  friction  disks  which 
form  part  of  the  driving  mechanism.  One  of  these 
disks,  a,  revolves  in  the  vertical  plane  parallel  with 
the  axis.  A  horizontal  driving  wheel,  b,  on  the 
spindle  has  a  narrow  leather  band,  c,  which  bears 
against  this.  The  leather-faced  wheel  is  adjustable 
vertically  and,  when  set  to  bear  upon  the  vertical 

266 


S3 


> 


02 


00 
Em 


CO 


CHAPTER  XVI 
DEILLIXG  :\lACniXEEY 

The  Sensitive  Drill. — Drilling  macliincs,  in  some 
form,  are  found  in  every  shop.  They  are  used  for 
drilling  round  holes  in  all  kinds  of  castings  and 
forgings;  for  tapping  or  threading  the  hok's;  for 
countersinking  or  making  a  tapered  enlargement  of  the 
upper  end  of  a  hole;  for  counterhoring  or  making  an 
annular  enlargement  of  the  upper  end  of  a  hole;  for 
reaming,  which  is  passing  a  reamer  through  the  hole 
to  increase  the  accuracy  of  form;  and  for  spot  facing, 
which  is  making  a  shallow  countei'hore  d(H'p  enough 
to  form  a  smooth  face  for  the  head  or  nut  of  a  ])olt. 

The  smallest  and  simplest  form  is  a  sensitive  drill, 
Figure  78.  It  consists  of  an  upright  standard,  a 
smooth  horizontal  table  on  which  to  rest  the  work, 
a  vertical  spindle  capal)le  of  holding  and  rotating  the 
drill,  and  means  for  feeding  eitlier  the  work  or  tlie 
drill,  usually  the  latter.  The  variations  in  speed  are 
orenerallv  obtained  bv  means  of  friction  disks  whicli 
form  part  of  the  driving  mechanism.  One  of  these 
disks,  a,  revolves  in  the  vertical  plane  parallel  with 
the  axis.  A  horizontal  driving  wheel,  )>,  on  tin* 
spindle  has  a  narrow  leather  band,  c,  which  bear> 
against  this.  The  leather-faced  wheel  is  adjustahl« 
vertically  and,  when  set  to  bear  upon  the  v(Mtic;if 

266 


I 


■:  i 


268 


THE  MECHANICAL  EQUIPMENT 


disk  near  its  rim,  will  drive  the  spindle  at  the  great- 
est speed.  By  lowering  it  toward  the  center  of  the 
vertical  wheel,  the  speed  may  be  reduced  to  zero.  By 
lowering  it  still  further,  the  direction  of  rotation  may 
be  reversed.  The  wheel,  b,  drives  the  spindle  by 
means  of  a  sliding  key,  or  spline,  and  is  retained  in 
its  proper  position  by  the  finger,  d,  while  the  spindle 
is  fed  downward  by  means  of  the  light  hand-lever 
shown  at  the  right.  In  some  types,  the  friction  disks 
are  arranged  at  the  base  of  the  upright,  and  in  others 
the  variations  in  speed  are  obtained  by  means  of 
cone  pulleys.  The  drill  is  often  tised  as  a  bench 
machine,  and  only  for  light  rapid  work  of  the  simplest 
nature. 

Upright  Drills. — The  commonest  type  of  drill  is 
the  standard  upright  drill  press,  shown  in  Figure  79. 
The  essential  elements  are  the  main  upright  or 
column,  the  table,  the  spindle,  and  the  driving  and 
feed  mechanism.  The  drill,  or  tool,  is  carried  in  a 
smooth  tapered  socket  at  the  lower  end  of  the  main 
spindle,  into  which  it  will  seat  itself  firmly  enough  to 
transmit  the  power  required  to  make  the  cut.  To  re- 
move it,  a  taper  key  or  drift  is  inserted  through  the 
slot,  a,  and  driven  across  the  end  of  the  shank  of  the 
drill,  which  forces  it  out  of  the  hole. 

In  most  upright  drills  the  lower  portion  of  the 
column  is  cylindrical,  as  shown,  and  the  table  is 
carried  on  a  swinging  arm,  which  is  capable  of  being 
raised  or  lowered  by  means  of  an  elevating  screw,  b, 
shown  at  the  right,  and  clamped  to  accommodate  dif- 
ferent types  of  work.  The  circular  table  is  carried  at 
the  end  of  this  arm  on  a  short  vertical  spindk,  the 


DRILLING  MACHINERY 


269 


center  of  which  is  at  the  same  distance  from  the 
frame  as  the  drill  spindle.  This  arrangement  of 
swinging  arm  and  rotatable  table  is  very  convenient 
in  the  drilling  of  bolt  holes  in  flanges.  A  flange  may 
be  clamped  concentrically  to  the  table,  and  the  center 
of  the  table  set  off  to  one  side  a  distance  equal  to  the 
radius  of  the  bolt  circle.  The  table  may  then  be 
rotated  about  its  center  and  the  successive  holes 
drilled  in  turn.  In  most  upright  drills  the  column 
branches  out  at  the  top,  one  branch  curving  forward 
to  carry  the  upper  bearing  of  the  spindle  and  its 
driving  mechanism,  the  other  branch  curving  back- 
ward to  carry  the  bearing  behind  the  upper  driving 
pulley. 

Details  of  the  Drive. — The  chief  strain  to  which 
the  column  is  subjected  is  the  upward  axial  pressure 
against  the  drill,  which  produces  a  bending  move- 
ment. In  many  drills  this  is  cared  for  by  the  addi- 
tion of  a  secondary  column  in  the  rear,  which  helps 
to  carry  this  strain.  The  lower  end  of  the  driving 
spindle  is  carried  in  the  sliding  head,  c,  which  is 
gibbed  to  a  vertical  slide,  on  the  front  and  upper 
portion  of  the  column.  The  spindle,  like  that  of  the 
horizontal  boring  machine,  has  two  motions — one  of 
rotation,  and  the  other  of  longitudinal  traverse.  It 
consists  of  a  vertical  steel  shaft  passing  through  two 
sleeves.  The  upper  one,  driven  by  the  bevel  gear,  e, 
imparts  the  rotary  motion  to  the  spindle  through  a 
sliding  key;  the  lower  sleeve  slides  vertically  without 
rotation,  carrying  the  spindle  up  and  down,  and  is 
actuated  by  a  rack-and-pinion  feeding  mechanism 
located  in  the  head.    The   upward   thrust   in  most 


I 


lei 


270 


THE  MECHANICAL  EQUIPMENT 


modern  drills  is  cared  for  by  ball  or  roller  thrust 
bearings,  which  are  clearly  seen  in  the  heavier  ma- 
chines, shown  in  Figures  80  and  81. 

In  many  machines  the  lower  head,  c,  Figure  79,  is 
cast  solid  with  the  column;  this  arrangement  gives  a 
stiffer  construction.  The  sliding  head,  however,  with 
its  adjustment  up  and  down,  is  more  convenient  for 
varying  heights  of  work,  gives  a  longer  vertical  move- 
ment to  the  spindle,  and  supports  it  close  to  the  drill 
at  all  times.  In  some  machines  the  sliding  head  itself 
moves  up  and  down  with  the  feed;  in  others  the  head 
is  clamped  and  the  spindle  is  fed  downward  through 
it.  The  latter  form  is  a  little  more  rigid,  while  the 
former  does  away  with  the  rack  and  pinion  on  the 
sleeve,  and  permits  of  a  longer  traverse.  In  addition 
to  the  adjustable  swinging  table,  most  upright  drilk 
are  provided  with  a  forward  extension  of  the  base 
which  is  planed  and  slotted  to  hold  large  work. 

The  driving  mechanism  consists  of  a  countershaft 
with  a  tight  and  a  loose  pulley,  and  a  cone  pulley 
usually  located  at  the  base  of  the  machine,  as  shown., 
The  upper  shaft  carries  the  secondary  cone  and  the 
necessary  gearing  for  the  speed  changes.  The  front 
end  of  the  shaft  carries  the  bevel  pinion  which  drives 
the  bevel  gear,  e,  and  through  it  the  main  spindle. 
All  except  small  drills  are  provided  with  power  feed, 
and  most  of  them  are,  or  may  be,  equipped  with  tap- 
ping attachments  used  for  threading  holes.  The 
various  adjustments  may  be  operated  by  hand  as  well 
as  by  power. 

Heavy  Duty  Drill-Presses.— While  the  circular  col- 
UMui  is  very  convenient  in  many  ways,  it  is  obviously 


271 


i,'f 


270 


THE  iMECHANICAL  EQUIPMENT 


modern  drills  is  cared  for  hv  ball  or  roller  thrust 
bearings,  which  are  clearly  seen  in  the  heavier  ma- 
chines, shown  in  Figures  Hi)  and  81. 

In  many  machines  the  lower  head,  c,  Figure  79,  is 
cast  solid  with  the  column;  this  arrangement  gives  a 
stiffer  construction.  The  sliding  head,  however,  with 
its  adjustment  up  and  down,  is  more  convenient  for 
varying  heights  of  work,  gives  a  longer  vertical  move- 
ment to  the  spindle,  and  supports  it  close  to  the  drill 
at  all  times.  In  some  machines  the  sliding  head  itself 
moves  up  and  down  with  the  feed;  in  others  the  head 
is  clamped  and  the  spindle  is  fed  downward  through 
it.  The  latter  form  is  a  little  more  rigid,  while  the 
former  does  away  with  the  rack  and  pinion  on  the 
sleeve,  and  permits  of  a  longer  traverse.  In  addition 
to  the  adjustable  swinging  table,  most  upright  drills 
are  provided  with  a  forward  extension  of  the  base 
which  is  planed  and  slotted  to  hold  large  work. 

The  driving  mechanism  consists  of  a  countershaft 
with  a  tight  and   a  loose  pulley,  and  a  cone  pulley 
usually  located  at  the  base  of  the  machine,  as  shown 
The  upper  shaft  carries  the  secondary  cone  and  tlie 
necessary  gearing  for  the  speed  changes.     The  front 
end  of  tlie  shaft  carries  the  bevel  pinion  which  drives 
the  bevel  gear,  e,  and  through  it  the  main  spindle 
All  except  small  drills  are  provided  with  power  feed. 
and  most  of  them  are,  or  may  be,  equipped  with  ta}i 
ping    attachments    used    for    threading    holes.     Tli< 
various  adjustments  may  be  operated  by  hand  as  well 
as  by   ()()wer. 

Heavy  Duty  Drill-Presses.— While  the  eireular  ce! 
uniii  is  very  eonvenient  in  many  ways,  it  is  obviousl^ 


IN 


J71 


272 


THE  MECHANICAL  EQUIPMENT 


DRILLING  MACHINERY 


273 


I 


limited  in  strength.  Heavy-dnty  drill  presses  for 
large  work  and  for  use  with  high-speed  steel  may 
take  the  form  shown  in  Figures  80  and  81;  the  frame 
is  a  heavy  box  section  designed  for  severe  service,  and 
the  tipper  and  lower  spindle  bearings  are  both  solid 
with  it. 

The  machine  shown  in  Figure  80  has  a  single- 
speed  belt  drive;  the  main  driving  pulley,  being  on 
the  other  side  of  the  machine,  is  not  shown.  The 
axis  of  the  driving  pulley  is  parallel  to  the  front  of 
the  machine,  an  arrangement  which  allows  the  ma- 
chine to  be  set  as  one  of  a  row  down  the  shop.  The 
speed  changes  are  provided  through  change  gears. 
The  feed  mechanism  is  very  powerful,  and  is  pro- 
vided with  a  safety  device  to  protect  the  driving 
mechanism  in  case  of  overload.  This  device  takes 
the  form  of  a  ** shearing  pin"  proportioned  to  let  go 
when  an  overload  is  reached.  The  swinging  table  is 
done  away  with,  and  an  adjustable  table  mounted 
on  heavy  guides  is  substituted,  as  in  Figure  80.  For 
the  still  heavier  machines,  shown  in  Figure  81,  the 
work  is  carried  on  the  slotted  floor  plate.  The  plane 
surfaces  at  the  front  of  the  uprights  on  the  latter 
machines  are  employed,  not  to  carry  work,  but  to 
support  guides  (not  shown),  which  may  be  used  to 
steady  the  spindle  when  desired. 

This  type  of  machine  is  similar  in  many  ways  to  a 
horizontal  boring  machine,  except  for  its  vertical  posi- 
tion, and  is  used  for  many  kinds  of  boring  operations. 
Figure  80  shows  a  set  of  tools  in  place  for  doing  a 
typical  boring  operation— the  turning  of  the  conical 
face  of  bevel-gear  blanks.    This  is  a  case  of  what  is 


known  as  **second  operation"  work.  The  blanks  in 
the  smaller  pile  at  the  left  show  that  a  hole  has 
already  been  drilled  and  one  side  has  been  faced. 
The  tool  head  is  equipped  with  a  pilot  bar,  a,  which 
enters  this  hole  and  centers  the  spindles  during  the 
heavy  cutting  operations,  which  here  include  facing 
the  top,  turning  the  hub,  and  facing  the  conical  sur- 
face. The  machines  shown  in  Figure  81  are  heavy 
enough  to  do  much  of  the  work  that  used  to  be  done 
on  a  boring  mill,  for  the  spindle  is  10  inches  in 
diameter  at  the  end.  The  one  in  the  foreground  is 
fitted  with  heavy  facing  tool  and  pilot  bar.  While 
technically  known  as  drilling  machines,  these  have 
really  passed  into  the  boring-machine  class. 

Radial  Drills. — As  the  work  grows  larger,  it  is 
easier  to  move  the  tool  about  the  work  than  to  shift 
the  work  under  the  tool.  A  class  of  drilling  ma- 
chines, known  as  radial  drills,  have  been  developed 
for  this  service.  These  are  known  as  plain,  half- 
universal,  or  full-universal  drills  according  to  the 
character  of  the  motion  that  may  be  given  to  the 
drilling  head.  In  the  plain  radial,  shown  in  Figure  82, 
the  drilling  head,  a,  has  a  motion  in  and  out  from 
the  column,  and  may  be  swung  radially  about  the 
column,  its  axis  at  all  times  remaining  vertical.  In 
the  half-universal,  the  head  swivels  in  a  vertical  plane 
parallel  to  the  face  of  the  arm,  so  that  the  spindle 
may  be  set  at  any  angle  in  that  plane.  In  the  full- 
universal,  the  radial  arm  itself  has  a  swiveling  motion 
in  addition.  Such  a  machine  is  shown  in  Figure  84. 
It  is  remarkably  flexible,  and  will  drill  a  hole  at  any 
angle. 


274 


THE  MECHANICAL  EQUIPMENT 


'J 


The  plain  radial  is  simpler,  easier  to  operate  and, 
because  it  has  fewer  joints,  is  more  accurate,  but  it 
is  of  course  more  limited  with  respect  to  the  work 
that  it  will  do.  The  base  of  the  radial  drill  has  a 
heavy  floor  plate  under  the  arm  for  carrying  the 
work.  These  are  often  fitted  with  a  removable 
slotted  table,  or  block,  as  shown,  to  accommodate 
lighter  work;  if  the  squared  surfaces  are  used,  holes 
may  be  drilled  at  right  angles.  Some  radials  are 
fitted  with  blocks  which  may  be  tilted  on  bearings, 
and  which  carry  a  round  swiveling  plate.  This  at- 
tachment gives  to  the  plain  radial  the  flexibility  of  a 
full-universal,  but  such  a  holding  device  will  not 
handle  as  large  work  as  a  full-universal  drill. 

The  Column  and  Drivings  Mechanism. — Of  the  sev- 
eral types  of  columns  the  favorite  is  the  double  cir- 
cular— a  section  is  shown  in  Figure  83.  The  inner 
column,  a,  is  part  of  the  fixed  frame  of  the  ma- 
chine. It  has  a  circular  ball  bearing,  b,  at  the  top, 
and  a  large  sliding  bearing,  c,  at  the  bottom,  which 
carry  the  outer  sleeve,  d.  The  downward  thrust  of 
the  weight  is  carried  on  the  ball  bearing,  e.  The 
large  bearing,  c,  at  the  lower  end  of  the  outer  sleeve, 
d,  is  split,  and  is  provided  with  a  clamp  operated  by 
the  handle,  b  (Figures  82  and  84),  which  binds  the 
surfaces  together,  and  clamps  the  outer  sleeve  and 
arm  in  any  position  desired. 

The  radial  arm  slides  on  the  smooth  cylindrical 
surface  of  the  exterior  column,  or  sleeve,  and  is  pro- 
vided with  an  elevating  screw,  c,  shown  in  Figure 
82,  to  raise  and  lower  it.  When  the  desired  height 
is  reached,  the  operating  screw  is  thrown  out  of  gear 


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274 


Tllb:  MKCIIANK  AL  EQllPMEiNT 


The  plain  radial  is  simpler,  easier  to  operate  and, 
because  it  has  fewer  joints,  is  more  aecurate,  but  it 
is  of  course  more  limited  with  respect  to  the  work 
that  it  will  do.  The  base  of  the  radial  drill  has  a 
heavy  floor  plate  under  the  arm  for  carrying  the 
work.  Thrse  are  often  fitted  with  a  removable 
slotted  table,  or  block,  as  shown,  to  acconunodate 
lighter  work;  if  the  scjuared  surfaces  are  used,  holes 
may  be  drilled  at  right  angles.  Some  radials  are 
titled  with  blocks  which  may  be  tilted  on  bearings, 
and  which  vnvvy  a  round  swiveling  plate.  This  at- 
tachment gives  to  the  plain  radial  the  flexibility  of  a 
full-universal,  but  sucli  a  holding  device  will  not 
handle  as  larue  work  as  a  lull-universal  drill. 

The  Column  and  Driving  Mechanism. — Of  the  sev- 
eral types  of  colunms  the  favorite  is  the  double  cir- 
cular— a  section  is  shown  in  Figure  S.'].  The  inner 
column,  a,  is  part  of  the  fixed  frame  of  the  ma- 
chine. It  has  a  circular  ball  bearing,  b,  at  the  top, 
and  a  large  sliding  ])earing,  c,  at  tlie  bottom,  w^liich 
carrv  the  outer  sleev(%  d.  The  downwai'd  thrust  of 
the  weight  is  cariied  o]i  the  ball  bearing,  e.  The 
large  bearing,  c,  at  tlie  lower  end  of  the  outer  sleeve, 
d,  is  split,  and  is  provided  with  a  clamp  operated  by 
the  handle,  b  (Figures  82  and  84),  wliich  binds  the 
surfaces  together,  and  clamps  the  outer  sleeve  and 
arm  in  any  position  desired. 

The  radial  arm  slides  on  the  smooth  cylindrical 
surface  of  the  exterior  column,  or  sleeve,  aud  is  pro- 
vided witli  an  elevating  screw,  c,  shown  in  Figure 
82,  to  raise  and  lower  it.  When  the  desired  heiglit 
is  reached,  the  operating  screw  is  thrown  out  of  ge.')^' 


t. 

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276 


THE  MECHANICAL  EQUIPMENT 


and  the  arm  is  clamped  to  the  sleeve  by  means  of  the 
handles  shown  at  the  left.  When  the  arm  is  thus 
clamped  to  the  sleeve,  it  becomes  practically  solid 
with  it.  All  the  rotary  motion  takes  place  in  the 
bearings,  b  and  c  (Figure  83),  at  the  top  and  bot- 
tom of  the  column,  while  the  vertical  motion  is  cared 
for  solely  by  the  joint,  d  (Figures  82  and  84),  be- 
tween the  outer  sleeve  and  arm.  The  radial  arm  is 
designed  to  carry  the  heavy  vertical  thrust  of  the 
tool. 

On  the  side  are  slideways,  e,  which  carry  the  drill 
head.  This  head  contains  the  mechanisms  for  re- 
volving the  spindle  at  the  proper  speed  for  the  power 
feed  of  the  drill,  for  stopping  them,  and  for  the  quick 
return.  The  spindle,  as  in  other  drills,  has  a  rotary 
and  a  vertical  motion.  The  spindle  is  graduated  at 
f,  so  that  the  depth  of  the  hole  may  be  known,  and 
some  machines  are  arranged  with  a  device  that  may 
be  set  to  disengage  the  feed  at  any  depth  desired. 

The  machine  is  driven  by  a  single-speed  pulley 
through  a  change  gear  box  at  the  base  of  the  column, 
thence  through  a  pair  of  beveled  gears  upward 
through  a  shaft,  g,  concentric  with  the  column,  to 
gears  located  on  the  top.  From  these  the  power  is 
transmitted  downward,  outside,  to  the  radial  arm, 
and  outward  to  the  mechanism  located  in  the  head. 
All  of  the  power  feeds  are  also  equipped  with  hand 
control  mechanisms.  In  some  drills  there  is  a  floor 
plate  on  each  side  of  the  column,  so  that  the  work 
may  be  set  up  on  one  side  while  drilling  operations 
are  going  on  at  the  other  side,  and  often  the  table  is 
at  the  side,  as  at  h  in  Figure  84.    In  the  full-univer- 


:N. 


27G 


THE  MECllAiMCAL  EiiLir.ME.NT 


us 


ami  tlie  arm  is  ('lanii)ed  to  liic  slccvo  l>y  means  of  tl 
liaiulles  siiown  at  the  left.  When  tlie  arm  is  tli 
clamped  to  the  sleeve,  it  heeomes  practically  solid 
Avith  it.  All  the  rotary  jiiotion  takes  place  in  tlie 
hearings,   h  and  c   (Figure  8:j),  at    the  top  and  bot- 


tom of  the  colunm,  while  tl 


le  vertical  motion  is  cared 


for  solely  by  the  joint,  d  (Figures  8l>  and  84),  be- 
tween the  outer  sleeve  and  arm.  The  radial  arm  is 
designed  to  carry  the  heavy  vertical  thrust  of  the 
tool. 

On  the  side  are  slideways,  e,  which  carry  the  drill 
head.  This  head  contains  the  mechanisms  for  re- 
volving tlie  spindle  at  the  proper  speed  foi'  the  power 
feed  of  the  drill,  for  stopping  tluvm,  and  for  the  quick 
return.  The  spindle,  as  in  other  drills,  has  a  rotary 
and  a  vertical  motion.  The  spindle  is  graduated  at 
f,  so  that  tlie  depth  of  the  hoh^  may  be  known,  and 
some  machines  are  arranged  with  a  device  that 


be  set  to  disengage  the  feed  at 


may 


any  depth  desired. 


The   machine   is   driven   by   a   single-spe(»d    pulley 
through  a  change  gear  box  at  {ho  base  of  the  cohnnn, 
thence    through    a    pair    of    beveled    gi^ars    u])wai'd 
through  a  shaft,  g,  conc(Mitric   Avith  the   column,  to 
gears  located  on  tlie  top.    From  these  i]w  power  is 
transmitted   downward,   outside,    to    tlie   j'adial    arm, 
and  outward  to  the  mechanism  located  in  the  liead. 
All  of  the  power  feeds  are  also  erpiipped  with  ban.! 
control  mechanisms.     In  some  di'ills  tluM-e  is  a  iloo] 
plate  on  each  side  of  the  column,  so  that  the  wor' 
may  be  set  np  on  one  side  while  drilling  operation 
are  going  on  at  the  other  side,  and  ot'tem  the  table  i 
at  the  side,  as  at  h  in  Figure  84.     In  the  full-unive' 


278 


THE  MECHANICAL  EQUIPMENT 


DRILLING  MACHINERY 


279 


I 


sal  the  driving  motion  is  carried  from  the  motor  to 
the  drill  through  shafts  located  in  the  axis  of  the 
swiveling  joints,  where  the  arm  turns  on  its  sup- 
porting piece  and  the  spindle  head  turns  on  the. 
saddle.  One  of  these,  i,  is  clearly  shown  in  Figure 
84,  coming  out  centrally  along  the  arm.  The  spindle 
at  the  center  of  the  head,  a,  which  the  shaft,  i, 
drives,  is  hidden  in  the  head. 

Multiple-Spindle  Drill.— Many  classes  of  work  call 
for  the  drilling  of  a  number  of  parallel  holes,  as,  for 
instance,  the  bolt  holes  in  a  flange.  The  multiple- 
spindle  drill  has  been  developed  to  drill  such  holes 
simultaneously.  In  this  type,  one  of  which  is  shown 
in  Figure  85,  the  frame  is  a  box-like  column  with  an 
adjustable  sliding  table.  Instead  of  the  single  spindle 
with  its  drill  socket  there  are  a  number  of  drill 
sockets,  a,a,  carried  in  adjustable  brackets,  b,b, 
mounted  on  the  basket-like  head  at  the  top  of  the 
machine.  Each  of  these  short  spindles,  with  its 
socket,  is  adjustable  in  and  out  and  sidewise,  and  is 
driven  by  a  double-universal  joint,  c,  from  a  corre- 
sponding fixed  upper  shaft,  c';  the  lower  ends  of  some 
of  these  may  be  seen  through  the  opening  in  the 
head. 

These  upper  shafts  are  fixed  in  position  and  ar- 
ranged in  a  circle  around  a  common  driving  pinion 
operated  from  the  large  horizontal  pulley  on  the  top 
of  the  machine.  This  pulley  is  driven  by  the  half- 
turn  belt,  which  extends  back,  horizontally,  over  the 
guide  pulleys  and  down  to  the  main  driving  pulley 
below.  When  this  pulley  is  rotated,  it  drives  all  of 
the  spindles  at  the  same  speed.    Any  number  of  the 


spindles,  from  one  to  the  full  number,  may  be  em- 
ployed as  desired;  those  not  used  are  pushed  off  to 
one  side  out  of  the  way. 

When,  for  instance,  it  is  desired  to  drill  an  eight- 
holed  flange,  eight  of  the  spindles  are  arranged  in  a 
circle  at  the  desired  radius,  the  drills  are  inserted, 
and  all  the  holes  are  drilled  at  the  same  time.  In 
the  machine  shown,  the  work  is  lifted  against  the 
drills,  as  this  arrangenient  somewhat  simplifies  the 
problem  of  driving.  To  permit  this,  the  front  of  the 
machine  carries  a  saddle,  d,  which  is  adjusted  to  the 
height  desired.  This  saddle,  d,  in  turn  carries  a  slide, 
e,  which  is  operated  by  a  rack  and  pinion  through  the 
hand  lever,  f.  The  table,  g,  is  bolted  to  the  slide,  e, 
and  moves  up  with  the  work  as  the  lever  is  pushed 
down;  stops  are  provided  to  limit  the  motion  when 
desired.  Other  makers  keep  the  table  still,  and  bring 
the  head  with  all  the  drill  spindles  down  toward  the 
work. 

For  certain  classes  of  work,  such  as  the  drilling  of 
the  holes  in  the  flanges  of  cast-iron  pipe,  the  ma- 
chine is  arranged  in  a  horizontal  position  on  a  long 
bed,  somewhat  like  a  lathe  bed,  and  two  drilling 
heads,  similar  to  the  one  shown,  are  arranged  one 
at  each  end.  Each  of  these  heads  carries  a  set  of 
drilling  spindles,  and  may  be  fed  inward  toward  the 
center,  drilling  all  of  the  holes  in  both  ends  at  the 
same  time. 

Drilling  Jigs. — ^Drilling  is  not  a  very  accurate 
operation,  as  there  is  a  heavy  reaction  against  the 
end  of  the  drill  which  tends  always  to  force  it  out  of 
line,  if  conditions  are  not  absolutely  right.    Further- 


^-  TT 


280 


THE  MECHANICAL  EQUIPMENT 


DRILLING  MACHINERY 


281 


1 1 


more,  the  spindle  frequently  projei^ts  some  distance 
from  the  bearings  and  the  drill  projects  from  the 
end  of  the  spindle,  conditions  increasing  the  tendency 
to  spring,  or  **run.''  In  manufacturing  practice,  this 
tendency  is  reduced  and  the  accuracy  of  the  drilling 
process  is  greatly  increased  by  the  use  of  drilling 
jigs.  These  may  vary  from  a  simple  template,  with 
bushings  in  it,  to  complicated  and  ingenious  devices.* 
The  function  of  the  jig  is  to  clamp  the  work  firmly 
in  position,  and  to  hold  in  the  correct  location  a  hard- 
ened steel  bushing  the  size  of  the  hole  to  be  drilled. 

This  bushing  is  usually  located  in  a  leaf,  which  is 
turned  down  into  position  after  the  work  is  in  place. 
The  hole  in  the  bushing  is  rounded  at  the  upper  end 
in  order  that  the  end  of  the  drill  may  find  its  way 
easily  into  the  hole;  the  bushing  should  be  set  as 
close  as  possible  to  the  surface  to  be  drilled.    As  the 
bushing  is  hardened,  the  drill  makes  no  impression 
upon  it,  and  the  former  acts  as  a  guide  to  hold  the 
drill  in  the  exact  location  desired.    More  than  one 
hole  may  be  drilled  in  the  jig,  and  these  holes  do  not 
necessarily  have  to  be  of  the  same  size.    Practically 
all  repetition  work  is  drilled  with  the  use  of  jigs,  and 
these  may  often  be  very  elaborate.     The  Ford  motor 
cylinder  base  is  drilled,  in  one  of  the  operations,  in  a 
jig  in   a   special   machine   that   has   forty-five   drills 
operating  simultaneously  from  four  sides. 

When  a  single  hole  is  to  be  drilled  in  an  ordinary 
drill  press,  a  prick  punch  mark  is  made  on  the  center 
of  the  hole,  and  a  circle  is  scribed  around  it  the  size 

*For  a  detailed  description  of  drilling  ji^s  see  "Tools  and  P.ii- 
terns."  by  Albert  A.  Dowd.  Factory  Manaj^ement  Course. 


of  the  hole.  The  hole  is  just  started  with  the  conical 
nose  of  the  twist  drill,  and  the  drill  is  then  with- 
drawn. If  it  is  found  that  the  hole  has  started  eccen- 
trically, part  of  the  material  is  chipped  away  on  the 
side  toward  the  center  and  the  drill  is  brought  down 
to  the  work  again.  As  there  the  material  is  then  less 
on  the  side  toward  the  center,  it  tends  to  run  over 
toward  that  side  and  to  correct  the  eccentricity.  This 
process  is  repeated  until  the  hole  is  started  true. 
This  is  skilled  work  and  takes  time — ^it  is  evident 
why  the  use  of  drilling  jigs,  which  obviate  this  diffi- 
culty, is  so  general. 

Work  Commonly  Done  on  Drill  Press.— For  very 
accurate  deep-hole  drilling  the  relative  rotation  of  the 
work  and  the  drill  is  reversed;  the  drill  is  held 
stationary  and  the  work  is  revolved.  This  arrange- 
ment is  less  convenient,  but  gives  a  more  accurate 
result,  and  is  the  method  used  in  drilling  the  long 
accurate  holes  required  in  gun  manufacture.  At  the 
beginning  of  this  chapter  a  number  of  operations  were 
mentioned,  which  are  done  on  a  drilling  press  in 
addition  to  ordinary  drilling.  Countersinking  and 
counterboring  are  second  operations  which  would 
naturally  be  done  on  a  drill  at  the  same  time  the  hole 
is  originally  made.  In  these  operations  usually  a 
pilot  bar  is  employed  which  enters  the  hole  and 
centers  the  cutting  tool  that  does  the  enlarging. 
Reaming  is  another  second  operation  which  naturally 
is  done  on  a  drill  press.  For  accurate  work,  the 
reaming  tool  is  connected  loosely  with  the  driving 
spindle,  so  that  the  spindle  merely  rotates  it,  and  in 
no  way  controls  its  position.    Thus  the  reamer  is 


■:    iiU 


.1 


282 


THE  MECHANICAL  EQUIPMENT 


allowed  to  find  its  own  center  and  do  true  work. 
Tapping  is  one  of  the  commonest  operations  per- 
formed on  the  drill  press,  and  most  drills  are  provided 
with  attachments  for  this  work.  In  most  cases  the 
connection  between  the  tap  and  the  driving  spindle 
IS  made  through  some  form  of  friction  drive  which 
transmits  enough  power  to  make  the  normal  cut.  If, 
through  carelessness  or  otherwise,  the  tap  bottoms  in 
the  hole,  the  friction  drive  slips  and  prevents  the 
breaking  of  the  tap. 

Heavy-duty  drills  are  used  for  many  operations  thaf 
mght  be  classed  as  boring  work.  By  the  use  of  pilot 
bars  and  self-contained  guiding  devices  in  fixtures  es- 
pecially designed  for  the  purpose,  accurate  work  may 
be  done  on  drill  presses  to  great  advantage,  and  they 
are  increasingly  used  for  this  class  of  work. 


CHAPTER  XVII 
PLANERS,  SHAPERS,  AND  SLOTTERS 

Definition  of  Field. — Flat  surfaces  may  be  finished 
with  a  reciprocating  cutting  tool  in  a  planer,  shaper, 
or  slotting  machine.  While  the  fields  of  these  ma- 
chines overlap  somewhat  they  are,  in  the  main, 
fairly  well  defined.  The  planer  is  used  for  long  and 
narrow  faces,  and  for  machining  a  number  of  pieces 
that  may  be  set  up  one  behind  the  other,  making,  in 
effect,  one  long  surface.  It  is  also  used  for  surfaces  that 
are  straight  in  one  direction,  but  not  necessarily  flat. 
One  good  example  is  the  top  of  a  lathe  bed.  Figure 
47,  in  which  the  flat  faces  and  V-ways  may  be  finished 
at  one  setting.  The  inside  surface  of  the  upright 
guides  in  a  drop  hammer,  shown  in  Figure  22,  is 
another  example.  Generally  speaking,  the  planer  is 
used  for  large  cuts  on  heavy  pieces.  The  feeding 
motion  is  given  to  the  tool,  and  the  cutting  stroke 
is  made  by  moving  the  work  past  the  tool. 

The  shaper  is  very  convenient  for  special  cuts  on 
small  work,  and  is  therefore  especially  suited  to  the 
class  of  work  done  in  the  tool  room.  In  the  standard 
type  of  shaper,  the  cutting  motion  is  given  to  the  table 
and  nearly  all  of  the  feeds  are  given  to  the  table 
carrying  the  work;  the  only  feed  given  to  the  tool  is  a 
hand  feed  downward.    The  slotting  machine  is  used 

283 


) 


4 


( H 


284 


THE  MECHANICAL  EQUIPMENT 


i 

,r|. 


on  medium-  and  large-sized  work,  for  edging  cuts, 
inside  faces,  and  keyways  that  are  to  be  at  right 
angles  to  some  face  which,  usually,  has  been  ma- 
chined in  a  previous  operation.  In  the  slotter,  as  in 
the  shaper,  the  working  motion  is  given  to  the  cut- 
ting tool,  and  the  feed  is  taken  by  the  table  carrying 
the  work.  The  stroke  of  the  cutting  tool  in  the 
shaper  is  horizontal,  and  in  the  slotting  machine  it  is 
vertical. 

Early  Types  of  Planers.^The  first  planer  of  any- 
thing like  modern  design,  of  which  we  have  record, 
was  built  by  Eichard  Eoberts  in  England  in  1817. 
The  machine  is  now  in  the  South  Kensington  Museum 
in  London.  Chisel  and  file  marks  on  the  bed  and 
ways  indicate  that  it  was  itself  made  without  the 
use  of  a  planer.  The  machine  was  small— it  took  in 
work  less  than  a  foot  wide;  the  table  was  operated 
by  hand  by  means  of  a  chain  drive.  Within  twenty 
years,  Joseph  Clement  built  a  planer  that  would 
take  in  w^ork  six  feet  square;  it  was  for  many  years 
known  as  *^The  Great  Planer."  Work  was  brought 
to  it  from  all  the  districts  about  London,  and  it  is 
said  to  have  earned  for  its  owner  $100  a  day  for  many 
years.  This,  by  the  way,  was  also  a  hand-operated 
machine. 

The  Modem  Planer.— Today  the  planer  is  found  in 
all  shops  that  do  medium-  and  large-sized  work.  It 
uses  the  standard  type  of  single-edged  cutting  tool, 
and  the  tool  equipment,  unlike  that  of  the  milling 
machine,  is  inexpensive  and  may  be  used  for  a  great 
many  purposes.  A  disadvantage  of  the  planer,  as 
well  as  of  other  machines  with  a  reciprocating  action, 


PLANERS,  SHAPERS,  SLOTTERS 


285 


is  that  it  has  an  idle  return  stroke.  In  the  early 
forms  of  planer  the  motion  was  derived  from  an 
ordinary  crank,  and  the  return  stroke  was  made  at 
the  same  speed  as  that  of  the  working  stroke.  The 
slow  return  stroke  has  long  since  been  eliminated  by 
the  use  of  some  form  of  driving  mechanism  that 
quickens  the  return,  and  so  cuts  down  the  idle  time. 
It  would  seem  comparatively  easy  to  make  a  planer 
that  would  cut  both  ways — many  have  been  tried. 
For  a  number  of  very  practical  reasons,  however,  they 
have  never  been  successful. 

The  flexibility  of  the  planer,  and  its  adaptability  to 
various  uses,-  require  a  skilled  mechanic  to  run  it. 
This  principle  is  general  throughout  the  whole  field  of 
machine  tools.  Adaptability  in  a  machine  tool  re- 
quires a  number  of  feeds  and  adjustments  that  call 
for  skill  in  setting.  When  a  tool  becomes  a  single- 
purpose  machine,  the  adjustments  may  be  simplified 
and  reduced  in  number  so  that  a  comparatively  un- 
skilled attendant  may  operate  it. 

Standard  Type  of  Planer. — The  standard  type  of 
planer  is  shown  in  Figure  86.  It  consists  of  a  deep, 
heavv  bed  which  has  accurately  machined  slidewavs 
along  the  entire  length  of  the  top.  A  heavy  platen, 
which  carries  the  "work  to  be  machined,  slides  on 
these  ways.  The  bed  is  hollow  and  rectangular  in 
cross-section,  is  heavily  ribbed,  and  carries  the  bear- 
ings, and  so  on,  for  the  mechanism  that  operates  the 
traverse  of  the  bed.  The  platen  must  be  long  enough 
to  carry  the  longest  piece  that  the  planer  will  have 
to  handle,  and  the  bed  must  be  long  enough  to  carry 
the  platen  and  to  permit  it  a  travel  equal   to  the 


I 

1 


f-m'} 


286 


THE  MECHANICAL  EQUIPMENT 


longest  cut  to  be  made.  The  length  of  the  bed  is, 
therefore,  a  little  less  than  the  length  of  the  platen, 
plus  that  of  the  longest  cut.  Accordingly  there  are 
about  20  inches  of  length  of  bed  for  each  foot  in  the 
length  of  the  platen. 

^  The  slideways  on  both  bed  and  platen  must  be  true, 
since  upon  their  correctness  depends  the  accuracy  of 
the  work.  They  should  be  liberal  in  area,  and  should 
provide  means  for  the  take-up  of  wear.  In  Ameri- 
can practice,  this  is  usually  done  by  making  at  least 
one  of  the  ways  of  V-section.  In  the  smaller  ma- 
machines,  both  of  the  ways,  a,a,  may  be  of  this  section, 
as  in  Figure  86  and  87.  But  when  the  platen  has 
considerable  width,  one  of  them  is  a  plain  flat  surface, 
and  its  only  function  is  to  give  a  vertical  support  to 
the  platen;  the  other  is  relied  on  to  guide  the  platen 
in  a  horizontal  plane.  The  heavy  planer  shown  in 
Figure  90  has  three  ways— a  V-way  in  the  middle,  and 
a  flat  one  on  each  side.  The  top  of  the  platen  is  pro- 
vided with  T-slots  and  holes,  which  aid  in  clamping 
down  the  work.  On  the  under  side  of  the  platen  is  a 
rack,  which  is  driven  either  by  a  gear  wheel  or  by  an 
endless  screw.  The  platen  has  no  motion  other  than 
that  of  reciprocation  along  the  ways  on  the  bed.  All 
the  feeding  motions  are  given  to  tlie  cutting  tool. 

Rack-and-Pinion  Drive.— With  the  rack-and-pinion 
drive,  the  power  is  usually  transmitted  to  the  table 
through  a  train  of  gears  housed  in  the  bed  from  tight 
and  loose  pulleys  at  the  side  of  the  machine,  which 
are  clearly  shown  at  b.  Figure  86.  Open  and  crossed 
belts  are  used  on  these  pulleys,  one  for  the  forward 
cutting  motion  and  the  other  for  the  quick  return 


FIGS.    86   AND   87.      STANDARD   PLANERS 
The  20  X  17-inch  type,  above,   is  made  by  Whitcomb-BlalsdeU  Ma- 
chine Tool  Co.    The  lower  view  shows  a  42-inch  Niles-Bement-Pond 

planer.  287 


286 


THE  MECHANICAL  EQUIPMENT 


longest  cut  to  be  made.  The  lengtli  of  the  bed  is, 
therefore,  a  little  less  than  the  length  of  the  platen, 
phis  that  of  the  longest  cut.  Accordingly  there  are 
about  20  inches  of  length  of  bed  for  each  foot  in  the 
length  of  the  platen. 

^  The  slideways  on  both  bed  and  platen  must  be  true, 
since  upon  their  correctness  depends  tlip  accuracy  of 
the  \york.     They  should  be  liberal  in  area,  and  should 
provide  means  for  the  take-up  of  wear.     In  Ameri- 
can practice,  this  is  usually  done  by  making  at  least 
one  of  the   ways  of  V-section.     In   the  smaller  ma- 
machines,  both  of  the  ways,  a,a,  may  be  of  this  section, 
as  in  Figure  8()  and  87.     But  when  the  platen  has 
considerable  width,  one  of  them  is  a  plain  flat  surface, 
and  its  only  function  is  to  give  a  vertical  support  to 
the  platen;  the  other  is  relied  on  to  guide  the  platen 
in  a  horizontal  plane.     The  heavy  planer  shown   in 
Figure  90  has  three  ways— a  V-way  in  the  middle,  and 
a  Hat  one  on  each  side.    The  top  of  the  platen  is  pro- 
vided with  T-slots  and  holes,  which  aid  in  clampin.ii 
down  the  work.    On  the  under  side  ol*  the  platen  is  a 
rack,  which  is  driven  either  by  a  geai-  wheel  oi-  by  an 
endless  screw.     The  platen  has  no  motion  other  than 
that  of  reciprocation  along  the  ways  on  the  bed.     All 
the  feeding  motions  are  given  to  tlie  cutting  tool. 

Rack-and-Pinion  Drive.— With  the  rack-and-pinion 
drive,  the  power  is  usually  transmitted  to  the  tabh 
through  a  train  of  gears  housed  in  the  bed  from  tiglii 
and  loose  pulleys  at  the  side  of  the  machine,  whicli 
are  clearly  shown  at  b,  Figure  86.  Open  and  crossed 
belts  are  used  on  these  pulleys,  one  for  the  forwiU'd 
cutting  motion   and   the  other  for  the  quick  retui' 


I 


VUiS.    8()    AND   87.       STANDARD    PLANF.KS 
llu'   20x  17-iiK-li    lypo.    above,    is    niado   by    Wbitonnb-Iilaisdt'll    Ma- 
'  iiiiu'  Tdul  Cit.     'riic  lower  view  sbows  a  42-iiu-b  Nnt'.s-lJeiaeiit-Pon<i 

planer.  2S7 


(I 


it 

I. 


w 


III 

II 


288 


THE  MECHANICAL  EQUIPMENT 


motion.  They  are  driven  from  a  countershaft  above, 
and  are  shifted  backward  and  forward  from  the  tight 
pulleys  to  the  loose  pulley.  Various  forms  of  shift- 
ing mechanism  have  been  developed  by  the  different 
tool-builders  for  this  purpose.  The  motion  required 
is  not  so  simple  as  it  might  seem,  for  two  belts  can  not 
be  on  the  loose  pulley  at  the  same  time;  hence,  one 
must  be  shifted  somewhat  ahead  of  the  other. 

The  shifting  of  the  belts,  with  the  resulting  re- 
versal of  the  motion  of  the  platen,  or  table,  is  con- 
trolled from  a  tripping  device  located  at  the  side  of 
the  bed.  This  usually  takes  the  form  of  a  lever,  c, 
which  may  be  thrown  by  hand  when  desired,  but 
which,  in  the  ordinary  operation  of  the  machine,  is 
thrown  by  two  adjustable  stops,  d,d',  located  on  the 
side  of  the  platen.  These  may  be  moved  along  the 
side  and  clamped  in  any  position  required.  The  stop, 
d,  at  the  front  end  of  the  platen,  strikes  the  lever,  c, 
at  the  end  of  the  cutting  stroke,  throws  out  the  main 
forward  drive,  and  throws  in  the  quick  return. 
When  the  plate  has  traveled  forward  to  the  point 
desired,  the  stop,  d',  reverses  the  drive  and  throws  out 
the  return  motion,  and  the  next  cutting  stroke  be- 
gins. With  the  stops  in  the  position  shown,  the 
platen  will  make  a  comparatively  short  stroke  near 
the  middle  of  its  possible  travel.  If  the  stops  were 
both  well  forward  to  the  left,  the  bed  would  make  a 
short  stroke  with  the  front  end  of  the  table  under  the 
tool;  with  the  stop,  d,  at  the  front  end,  and  d'  well  to 
the  rear,  the  platen  would  make  a  full  stroke  and  the 
tool  would  make  a  cut  for  the  entire  length  of  the 
capacity  of  the  machine. 


PLANERS,  SHAPERS,  BLOTTERS 


289 


The  Uprights. — Either  cast  solid  or  bolted  firmly 
to  the  sides  of  the  bed,  are  the  two  uprights  that 
carry  the  cross  rail  and  the  tool  heads.  These  up- 
rights are  usually  two  in  number,  one  on  each  side, 
and  the  tables  passes  between  them.  The  bracing 
of  the  uprights  is  usually  parabolic  in  form — as  in 
Figures  86  to  88 — the  correct  design  for  maximum 
strength  to  withstand  the  main  thrust  of  the  tool  as 
the  work  comes  forward  on  the  cutting  stroke.  The 
brace  across  the  top  helps  the  uprights  to  withstand 
the  side  pressure,  which  is  also  present,  and  which 
may  be  very  considerable. 

On  the  front  of  the  uprights  are  machined  slide- 


PIG.  88.      24  BY  24  BY  24-INCH  CRANK  PLANER 
Cincinnati  Shaper  Co. 


288 


TIIH   MKCJIAXICAL   KQClPAfEXT 


PLANERS.  SI!AIM:RS,  SLOTTERS 


28!) 


motion.  Tliey  ai'o  driven  from  a  eonntci'sliaft  above, 
and  avo  sliil'tcd  backward  and  forward  from  tlie  tight 
pulleys  to  the  loose  pulley.  \'ai*ious  forms  of  shift- 
ing meehanism  have  been  developed  by  the  different 
tool-l)uilders  for  this  ])urpose.  The  motion  required 
is  not  so  simple  as  it  might  sec^n,  for  two  belts  ean  not 
be  on  th(»  loose  pulley  at  the  same  time;  hence,  one 
nuist  be  shifted  sonu*what  ahead  of  the  other. 

The   shifting  of  the    belts,   with   the    resulting   re- 
versal of  the  motion  of  the  platen,  or  table,  is  eon- 
trolled  from  a  tripping  device  located  at  the  side  of 
the  bed.     This  usually  takes  the  form  of  a  lever,  c, 
which   may   be   thrown    bv   hand    when   desired,    but 
which,  in  the  ordinai'y  operation   of  the   machine,   is 
thrown  by  two  adjustable  stops,  (U\\  located  on  the 
side  of  the  platen.     These  mav   be  moved  alonii-  the 
side  and  clamped  in  any  position  re({uired.     The  sto|), 
d,  at  the  front  end  of  the  platen,  strikes  the  lever,  c, 
at  the  end  of  the  cutting  stroke,  throws  out  the  nuiiii 
forward    drive,    and    throws    in    the    (piick    return. 
When   the   plate  has   traveled    forward    to   the   point 
desired,  the  stof),  d',  I'everses  the  drivi*  and  throws  out 
the   retui'u   motion,   and   the   next   cutting  stroke   be 
gins.     With    the    stops    in    the    position    shown,    the 
platen  will  nudvc  a  comparatively  short  stroke  near 
the  middle  of  its  possible  travel.     If  the  stops  were 
both  well  forward  to  the  left,  the  bed  would  nud;e  ;• 
short  stroke  with  the  fi'ont  end  of  the  table  undcM*  the 
tool;  with  the  stoj),  d,  at  the  front  end,  and  d'  well  to 
the  rear,  the  platen  would  make  a  full  stroke  and  tho 
tool    would   make  a   cut    for   the  entire   length   of  tin 
capacity  of  the  machine. 


The  Uprignts. — Either  cast  solid  or  l)olted  iirmly 
to  tli(^  sides  of  the  bed,  are  the  two  u[)rights  that 
cari'y  the  cross  rail  and  the  tool  heads.  Tli(\<e  up- 
rights are  usually  two  in  number,  one  on  each  side, 
and  the  tables  passes  belween  them.  The  l)i*acing 
of  the  uprights  is  usually  j)arabolic  in  form — as  iu 
Figures  8(j  to  88 — the  cori'ect  design  for  maxinmm 
strength  to  withstand  the  nuiin  thrust  of  the  tool  as 
the  work  comes  forward  on  the  cutting  stroke.  The 
brace  across  the  to})  helps  the  u})rights  to  withstand 
llie  side  pressure,  which  is  also  present,  and  ^vhich 
mav  be  vei'v  considerable. 

On   the   front   of  the   upi-ights   ai"e  machined   slide- 


FiG.  88.     24  BV  24  BY  24-iNrH  crank  planer 
CiiK'imuni  Sluipcr  (V>. 


ii» 


290 


THE  MECHANICAL  EQUIPMENT 


PLANERS,  SHAPERS,  SLOTTERS 


291 


Dl 


i 


il 


ll^ 


ways,  to  which  the  cross  rail  is  gibbed;  elevating 
feed  screws  in  the  slideways  operate  the  two  ends 
of  the  cross  rail  up  and  down.  The  elevating  screws 
are  connected  across  by  a  common  operating  shaft,  e, 
to  operate  in  unison  and  insure  parallelism  in  the 
motion  of  the  two  ends  of  the  rail.  On  the  rail  are 
mounted  one  or  more  saddles,  which  carry  the  tool 
heads. 

In  small  planers  there  will  be  one  of  these  heads, 
as  shown  in  Figures  86  and  88,  but  on  all  medium- 
and  large-sized  planers  there  are  two  heads.  When 
there  are  two  heads,  the  cross  rail  is  made  long 
enough  to  allow  the  full  motion  across  the  platen  of 
either  head.  The  tool  head,  in  all  cases,  has  a  sliding 
member,  f,  which  has  a  cross  feed,  and  which  carries 
a  tool-holder.  This  head,  with  its  feeding  screw, 
may  be  indexed  at  any  angle,  and  the  cutting  tool 
may  be  fed  downward  on  that  angle  when  desired. 
The  cutting  tool  is  carried  by  a  clamp,  g,  shown  on  a 
leaf,  or  clapper,  h,  which  is  pivoted  at  its  upper  end. 
The  purpose  of  the  pivot  is  to  allow  the  tool  to  lift 
clear  of  the  work  and  to  ride  upon  it  during  the  re- 
turn stroke.  When  the  work  has  run  past  the  tool  on 
the  return  stroke,  the  leaf  with  the  cutting  tool  drops 
back  into  place  and  is  ready  for  the  next  cut. 

Feed  Motions. — On  all  planers  of  any  considerable 
size,  the  various  feed  motions  are  power-driven  as 
well  as  hand-operated.  These  motions  are  as  follows: 
First,  a  downward  feed  of  the  cutting  tool  in  the 
head,  which  as  said  before,  may  be  set  to  operate  at 
an  odd  angle;  second,  each  of  the  heads  has  an  inde- 
pendent traverse  feed  along  the  cross  rail;  and,  third. 


the  cross  rail  as  a  whole  has  a  feed  up  and  down  on  the 
uprights.  The  various  power  feeds  are  arranged  to 
take  place  at  the  beginning  of  the  return  stroke,  and 
the  tool  is  stationary  during  the  working  stroke.  The 
mechanism  controlling  these  feeds  is  operated  from 
the  vertical  rack,  i,  on  the  outside  of  the  right-hand 
upright. 

Since  the  axes  of  most  of  the  shafts  in  the  main 
drive  are  at  right  angles  to  the  motion  of  the  table, 
the  driving  pulleys  are  generally  arranged  at  right 
angles  to  the  machine,  as  shown  in  Figure  86.  This 
plan  usually  necessitates  setting  the  length  of  the 
planer  across  the  shop,  in  order  to  place  the  driving 
pulleys  parallel  to  the  line  shafting,  a  position  which 
may  be  inconvenient  and  obstruct  the  floor.  To  avoid 
this  the  axis  of  the  driving  pulleys  may  be  set  parallel 
to  the  machine,  as  shown  in  Figure  87,  an  arrangement 
which  permits  long  planer  beds  to  be  placed  length- 
wise of  the  shop. 

The  spiral-gear  drive,  introduced  by  William  Sel- 
lers, of  Philadelphia,  does  away  with  most  of  the 
reducing  gears  necessary  in  a  spur-gear  drive.  The 
rack  underneath  the  platen  is  operated  by  a  worm, 
or  ** endless  screw,"  carried  on  the  end  of  a  shaft; 
this  shaft  extends  outward  at  an  angle  to  the  side 
of  the  main  bed,  where  it  is  driven  by  bevel  gears 
from  pulleys,  which  may  stand  either  at  right  angles 
or  parallel  to  the  bed.  It  is  used  on  the  larger  sizes 
of  planers,  and  has  the  advantage  of  great  strength, 
simplicity,  and  smoothness  of  action. 

In  recent  years,  belts  have  been  done  away  with 
entirely  on  many  planers  and  the  machine  is  driven 


*  I 


!(; 


I"  1. 


292 


THE  MECHANICAL  EQUIPMENT 


by  a  reversing  electric  motor  directly  coupled  to  the 
driving  shaft  in  the  bed  of  the  planer,  as  in  Figure 
89.  The  reciprocation  of  the  table  is  accomplished 
by  a  reversal  of  the  current  in  the  motor,  controlled 
by  stops  on  the  side  of  the  bed  similar  to  those  de- 
scribed in  connection  with  Figure  86. 

Special  Types  of  Planers.— Small  planers  may  be 
operated  by  a  Whitworth  quick-return  motion  similar 
to  that  shown  in  Figure  96.  These  are  known  as  crank 
planers.  The  stroke  is  rapid  and  smooth  in  action,  and 
may  be  varied  in  length  and  position  as  in  the  case  of 
the  belt-driven  planer.  This  type  of  planer  is  always 
of  comparatively  short  stroke.  The  one  shown  in  Fig- 
ure 88  has  a  stroke  of  24  inches. 

Figure  89  shows  a  modification  of  the  standard  type 
of  planer,  known  as  the  open-side  planer.     One  of 
the    housings    is    eliminated    and    the    cross-rail    is 
carried    on    a   heavy    extension    arm    or    knee    that 
reaches  across  the  table  from  a  heavy  upright.     The 
upright  has  a  box  section  capable  of  withstanding  the 
torsion  produced  by  the  pressure  on  the  tool.     The 
ordinary  type  of  planer  is  limited  to  work  that  can 
pass  between  the  uprights.    In  this  type,  work  may 
be  clamped  on  the  table,  which  extends  over  to  one 
side,  and  the  machine  is  therefore  capable  of  planing 
work  that  is  wider  than  the  table.    Large  planers,  of 
both  the  standard  and  the  open-side  type,  may' be 
equipped  with  tool  heads  on  the  uprights  as  well  as 
on  the  cross  rails,  for  machining  the  sides  of  a  cast- 
ing while  the  rail  heads  are  working  on  the  top. 
One  of  these  side  heads  is  shown  in  Figure  89.    Open- 
side  planers  are  sometimes  provided  with  an  auxiliary 


PLANERS,  SHAPERS,  BLOTTERS 


293 


FIG.  89.      OPEN  SIDE  PLANER 
Cleveland  Planer  Works. 

upright,  which  may  be  bolted  on  the  other  side  of  the 
frame  to  support  a  fourth  tool  head. 

Figure  90  shows  one  of  the  largest  planers  ever  built. 
This  huge  machine  is  60  feet  long  and  weighs  845,000 
pounds.  The  table  is  32  feet  long,  14  feet  wide,  slides 
on  three  ways— the  center,  a,  is  a  V-way  and  the  two 
outside  ones,  b,b,  are  flat— and  is  driven  with  two  steel 
**buir'  wheels  running  in  racks,  c,c,  15  inches  wide. 
The  main  drive  is  operated  by  a  100-horsepower  motor, 
and  the  various  feeds  and  other  motions  are  operated 


i  i 


**t"l;l|> 


XiO 


TIIK  Mi:(  HANK  AL   Kl^UIPMKNT 


PLAMvRS.  SlIAPEHS.  SLOTTHRS 


by  a  reversing  cloclric  iriolor  directly  coupUhI  to  tlie 
driving  slial't  in  tlh'  hod  of  the  planer,  as  in  figure 
89.  The  reciprocation  of  llie  table  is  accomplished 
hy  a  reversal  of  the*  current  in  the  motor,  controlled 
ij  stops  on  the  side  of  the  hed  similar  to  those  de- 
schl)ed  in  connection  with  Figure  SG. 

Special  Types  of  Planers.— Small  planers  mixy  he 
operated  hy  a  Whitworth  <piick-return  motion  similar 
to  that  shown  in  Figure  !)(i.  Th(\^e  are  known  as  crank 
planers.  Tiie  stroke  is  rapid  and  smooth  in  action,  and 
nuiy  he  varied  in  length  an<l  position  as  in  the  case  of 
the  helt-driven  planer.  1'his  type  of  i)laner  is  always 
of  comparatively  short  stroke.  The  one  shown  in  Fig- 
ure 8S  has  a  stroke  of  24  inches. 

Figure  89  shows  a  modilication  of  tlie  stanchird  type 
of  planer,   known   as   the   ojjen-side   planer.     One  of 
the    housings    is    eliminated    and    the    cross-rail    is 
carried    on    a    heavy    extension    aim    or    knee    that 
reaches  across  the  table  from  a  heavy  U})right.     The 
upright  has  a  box  section  capable  of  withstanding  the 
torsion   produced    by   the   pressure   on   the   tool.     The 
ordinary  type  of  planer  is   limited  to   work  that  can 
pass  between  the  uprights.     In  this  type,  work  may 
be  clamped  on  the  table,  which  extends  over  to  one 
side,  and  the  machine  is  therefoi'e  capable  of  planing 
work  that  is  wider  than  the  tabl(\     T^arge  planers,  ol 
both   the  standard   and   the  open-side   type,   may   be 
equipped  with  tool  heads  on  tlu^  uprights  as  well  a^ 
on  the  cross  rails,  for  machining  the  sides  of  a  cast 
ing   wliile   the   rail    heads   are   working   on    the   to). 
One  of  these  side  heads  is  shown  in  Figure  89.    Opei, 
side  planers  are  sometimes  piovided  with  an  auxiliai  v 


FIG.  SO.      OPEN  Sn^E  PLANER 
Clevolaml  IMnnor  AVorks. 

upright,  Avliicli  may  be  bolted  on  tlie  otluu'  side  of  the 
frame  to  support  a  fourth  tool  head. 

Figure  90  shows  one  of  the  largest  planers  ever  built. 
Tlus"huge  machine  is  (iO  feet  long  and  weighs  84r),0()() 
l.ounds.^  The  table  is  :V1  U^'i  long,  U  f(H^t  wide,  slides 
nu  three  ways— the  center,  a,  is  a  V-way  and  the  two 
outside  ones",  b,b,  are  (lat— and  is  driven  with  two  steel 
•'buir'  wheels  running  in  racks,  c,c,  IT)  inches  wide. 
The  main  drive  is  oju'rated  ])y  a  lOO-horsei.ower  motor, 
;md  the  various  feeds  and  otlier  motions  are  operated 


.11 

I  PI 


294 


THE  MECHANICAL  EQUIPMENT 


• 

by  independent  motors,  so  that  the  total  motor  capacity 
is  2071/2  horsepower.  The  stroke  of  the  table  is  30 
feet,  the  width  between  uprights  14  feet  4  inches,  and 
the  maximum  height  from  the  top  of  the  table  to  the 
under  side  of  the  cross  rail  is  12  feet  3  inches.  In 
the  main,  the  machine  is  of  the  usual  planer  type,  but 
it  has,  in  addition,  several  unusual  features.  Slotter 
bars,  d,  with  an  8-foot  stroke,  are  incorporated  in  the 
rail  heads,  and  one  of  these  heads  is  provided  with  a 
power  cross-motion  for  transverse  planing.  The  ma- 
chine is  therefore  capable  of  planing  in  three  direc- 
tions with  one  setting  of  the  work  upon  the  table. 

A  special  type  of  large  planer,  shown  in  Figure  91, 
is  used  in  the  Midvale  Steel  Works  for  planing  armor 
plates.  Such  work  is  so  heavy  that  it  is  easier  to 
move  the  machine  with  the  cutting  tool  over  the  work 
than  to  move  the  work  under  the  tool.  The  plate  is 
set  on  the  slotted  bed  between  the  horizontal  rails, 
and  the  cutting  tool,  with  the  head  and  two  uprights, 
is  moved  across  the  work.  The  motion  of  the  two 
uprights  is  derived  from  heavy  screws,  which  are  ar- 
ranged to  operate  in  unison  to  insure  parellelism  of 
motion.  In  this  case,  the  motions  of  the  cutting 
stroke  and  of  the  various  feeds  are  given  to  the 
cutting  tool,  and  the  work  remains  stationary. 

Another  screw-driven  planer,  shown  in  Figure  92, 
consists  of  a  large  vertical  head,  a,  which  has  a  hori- 
zontal motion  along  the  lower  bed.  This  head  has 
vertical  guideways  and  a  heavy  saddle,  b,  which 
carries  the  cutting  tool.  This  saddle  has  a  screw- 
operated  vertical  motion,  which  may  be  used  for  ver- 
tical cuts,  the  main  head  or  upright,  a,  being  clamped 


PIG.  90.      12  BY  14  BY  30-FOOT  PLANER 

FIG.  91.      ARMOR  PLATE  PLANER 

JJIles-Bement-Pond  Co, 

295 


294: 


THE  MECHANICAL  EQUIPMENT 


by  indepi^ndont  motors,  so  tluit  the  total  motor  capacity 
is  207 y^  horsepower.  The  stroke  of  the  table  is  30 
feet,  the  width  between  uprights  14  feet  4  inches,  and 
the  maxiimnn  height  from  the  top  of  the  table  to  the 
under  side  of  the  cross  rail  is  12  feet  3  inches.  In 
the  main,  the  machine  is  of  the  usual  planer  type,  but 
it  has,  in  addition,  several  unusual  features.  Slotter 
bars,  d,  with  an  8-foot  stroke,  are  incorporated  in  the 
rail  heads,  and  one  of  these  heads  is  provided  with  a 
pow(M'  cross-motion  for  transverse  planing.  The  nia- 
ciiine  is  therefore  capable  of  planing  in  three  direc- 
tions with  one  setting  of  the  work  upon  the  table. 

A  special  type  of  large  planer,  shown  in  Figure  91, 
is  used  in  the  Midvale  Steel  Works  for  planing  armor 
plates.  Such  work  is  so  heavy  that  it  is  easier  to 
move  the  machine  with  the  cutting  tool  over  the  work 
than  to  move  the  work  under  the  tool.  The  plate  i> 
set  on  the  slotted  bed  between  the  horizontal  rails, 
and  the  cutting  tool,  with  the  head  and  two  uprights, 
is  moved  across  the  work.  The  motion  of  the  two 
uprights  is  derived  from  heavy  screws,  which  are  ar- 
ranged to  operate  in  unison  to  insure  parellelism  of 
motion.  In  this  case,  the  motions  of  the  cutting 
stroke  and  of  the  various  feeds  are  given  to  the 
cutting  tool,  and  the  work  remains  stationary. 

Another  screw-driv(^n  planer,  shown  in  Figure  92, 
consists  of  a  large  vertical  head,  a,  which  has  a  hori- 
zontal motion  along  the  lower  bed.  This  head  ha> 
vertical  guideways  and  a  heavy  saddle,  b,  wliicli 
carries  the  cutting  tool.  This  saddle  has  a  screw 
operated  vertical  motion,  which  nuiy  be  used  for  ver 
tical  cuts,  the  main  head  or  upright,  a,  Ix^ng  clamp< - 


FIG.  90.      12  13Y  14  BY  oO-FOOT  PLANER 

FIG.  91.      ARMOR  PLATE  PLANER 

Niles-noTnfnt-ron<l   Co. 

29.1 


''  fill 


i 


II 


f 


296 


THE  MECHANICAL  EQUIPMENT 


FIG.  92.      SCREW-DRIVEN  PLANER  FOR  WORK  IN  TWO  DIRECTIONS 

Niles-Bement-Pond  Co. 

to  the  bed;  or,  the  saddle  may  be  clamped  to  the  up- 
right and  the  head,  a,  moved  sidewise  to  plane  hori- 
zontal cuts.  With  this  type  of  machine  it  is  possible  to 
make  cuts  at  right  angles  to  each  other  on  the  end 
of  a  heavy  piece  at  a  single  setting.  The  machine  is 
driven  by  a  reversing  motor. 

Skill  and  judgment  are  required  in  clamping  work 
to  a  planer  table,  for  the  work  must  not  slip,  must 
not  spring  in  any  direction  under  any  of  the  cuts, 
and  yet,  however  tight  the  clamping,  it  must  not 
distort  the  piece  in  any  way.  Long-pitch,  helical 
grooves  may  be  cut  on  a  planer  by  mounting  the 


PLANERS,  SHAPERS,  SLOTTERS 


297 


piece  on  centers  carried  on  the  table,  and  giving  to 
the  work  a  rotary  feed  that  is  directly  proportional 
to  the  longitudinal  travel.  Occasionally  long,  curved 
surfaces  are  planed  by  mounting  on  the  table  beside 
the  work  a  ** former,"  which  causes  the  cutting  tool 
to  rise  and  fall  as  the  table  passes  under  it.  The 
combination  of  the  two  motions  generates  an  irregular 
cut  which  follows  the  curve  of  the  *' former."  Fre- 
quently a  number  of  cutting  tools  are  set  one  behind 
the  other  in  the  tool-holder,  to  make  successive  cuts 
at  the  same  pass  from  the  rough  to  the  finished  sur- 
face. Other  points  in  regard  to  the  setting  of  planer 
tools  have  been  mentioned  in  the  chapter  on  ^'Cutting 
Tools." 

The  Shaper  and  Its  Work.— The  shaper  was  in- 
vented by  James  Nasmyth,  and  was  for  many  years 
known  among  the  English  mechanics  as  *' Nasmyth 's 
Steel  Arm,"  It  was  improved  by  Whitworth,  who 
introduced  the  quick-return  motion,  and  gradually 
took  the  form  that  is  known  today.  Figure  93  shows 
a  modern  shaper.  It  consists  essentially  of  a  stiff, 
box-like  frame  carrying  a  vise  or  jaw  mounted  in 
front  on  a  slotted  table,  or  support,  and  capable  of 
vertical  and  transverse  motion  under  hand  or  power 
feed.  The  top  of  the  frame  is  gibbed  to  receive  a 
reciprocating  ram,  a,  carrying  on  the  front  end  a 
tool  head  which  may  be  set  at  any  angle  and  which 
has  an  independent  hand-operated  cross  feed,  b. 

On  the  slide  of  this  tool  head  is  a  tool  post,  and 
clapper  box,  c,  similar  to  those  used  on  the  planer. 
The  work  is  clamped  in  the  jaws  below,  and  the  tool 
is  reciprocated  across  the  work.    Except  for  the  hand 


Mi 


i    \ 


n 


29(> 


THE   MECIIAMCAL  KQUIPMENT 


PLANERS,  SllAPKKS,  SEOTTKRS 


lil)* 


FIG.  92.      SCRE\V-DKI\  i:X  PLANER  FOR  WORK  IN  TWO  DIRECTIONS 

Niles-lienient-Poinl    ( 'o. 

to  tlic  I)(m1;  or,  {\w  saddle  may  hu  clainjx'd  to  the  up- 
riglit  and  the  li<'ad,  a,  moved  siilcwisc  to  j)laiie  hori- 
zontal cuts.  Witli  this  type  of  iiiaelniic  it  is  possihh'  to 
make  cuts  at  right  ani»Ies  to  eacli  othei-  on  the  end 
of  a  lieavy  piece  at  a  .single  setting.  The  maehine  is 
drixcn  hy  a  I'eversing  motor. 

Skill  and  Jndgment  are  required  in  elamping  work 
to  a  phiner  table,  for  the  work  nmst  not  slip,  must 
not  spring  in  any  direction  under  anv  of  the  cuts, 
and  yet,  however  tight  the  elamping,  it  must  nol 
distort  the  piece  in  any  way.  Long-pitch,  helical 
grooves    may    he   cut    on    a    ph-iner    hy    mounliim-    thr 


piece  on  centers  carticd  on  tlie  ta]>K',  and  giving  to 
the  work  a  rotary  I'eed  that  is  directly  pi'oporlional 
to  the  longitudinal  travel.  Occasionally  long,  curved 
surfaces  are  planed  hy  mounting  on  the  table  beside 
the  work  a  '^former,"  which  causes  the  cutting  tool 
to  rise  and  fall  as  the  table  passes  under  it.  The 
combiiuition  of  the  two  motions  generates  an  irregular 
cut  which  follows  the  curve  of  the  'former."  Fre- 
quently a  number  of  cutting  tools  are  set  one  Ijehind 
the  other  in  the  tool-holder,  to  make  successive  cuts 
at  the  same  pass  from  the  rough  to  the  finished  sur- 
face. Other  i)oints  in  regard  to  the  setting  of  planer 
tools  have  been  mentioned  in  the  chapter  on  "'Cutting 
Tools.'' 

The  Shaper  and  Its  Work.— The  shaper  was  in- 
vented bv  dames  Xasmvth,  and  was  for  many  years 
known  among  the  English  mechanics  as  ^^Xasmyth's 
Steel  Arm.''  It  was  impi'oved  by  Whitworth,  who 
introduced  the  quick-return  motion,  and  gradually 
took  the  form  that  is  known  today.  Figure  93  shows 
a  modern  shaper.  It  consists  essentially  of  a  stiff, 
box-like  frame  carrying  a  vise  or  jaw  mounted  in 
front  on  a  slotted  table,  oi-  su])port,  and  capal)le  of 
vei-tical  and  transverse  motion  under  hand  or  power 
IVed.  The  top  of  the  frami'  is  gibbed  to  receive  a 
reciprocating  ram,  a,  carrying  on  the  front  end  a 
tool  head  which  mav  be  set  at  anv  angle  and  which 
has   an   itidependent   hand-operated   cross   feed,   b. 

(hi  the  slide  of  this  tool  head  is  a  tool  post,  and 
clapper  box,  c,  similar  to  those  used  on  the  planer. 
The  work  is  clampcnl  in  the  jaws  below,  and  the  tool 
is  I'ecipi'ocated  across  the  work.    Exce])t  for  tlu'  hand 


V( 


\n 


\  .1 


298 


THE  MECHANICAL  EQUIPMENT 


FIG.  93.      STANDARD  SHAPER 
Gould  &  Eberhardt. 

feed  on  the  head,  all  the  feeds  are  given  to  the  work- 
holder.  In  the  larger  sizes  of  shaper,  provision  is 
made  for  an  adjustable  support,  d,  which  extends 
from  the  table  to  the  base,  to  preclude  springing  on 
heavy  cuts.  There  are  various  types  of  shaper  drives, 
all  of  them  arranged  to  give  a  slow,  powerful  motion 
on  the  forward  stroke  and  a  quick  return.  The  stroke 
may  be  varied  from  zero  up  to  the  full  capacity  of 
the  machine,  and  the  ram  may  be  set  forward  or 


PLANERS,  SHAPERS,  SLOTTERS 


299 


backward  with  reference  to  the  frame,  so  that  short 
cuts  may  be  made  on  different  parts  of  a  piece.  The 
machine  shown  has  the  standard  equipment,  but  spe- 
cial attachments  are  used,  such  as  tilting  and  swiveling 
tables,  which  permit  the  shaping  of  a  curved  surface, 
and  index  centers,  somewhat  similar  to  those  that  will 
be  described  in  connection  with  universal  milling  ma- 
chines, which  permit  the  cutting  of  long  spirals.  The 
shaper  is  a  good  tool-room  machine,  and  is  much 
better  for  small  work  than  the  planer.  The  type  of 
drive  used  gives  a  more  accurate  control  of  the 
length  of  stroke  than  can  be  given  by  the  shifting 
belts  used  on  a  planer.  For  accurate  special  work, 
such  as  die-sinking,  it  is  an  advantage  to  have  the 
work  stationary,  in  order  that  the  action  of  the 
cutting  tool,  when  machining  to  a  line,  may  be 
closely  watched. 

Construction  and  Operation  of  the  Shaper. — ^In 
most  shapers,  the  tool  cuts  on  the  stroke  toward  the 
operator.  In  some  types,  however,  this  is  reversed 
and  the  cutting  is  done  on  the  inward  stroke.  The 
latter  types  are  known  as  draw-cut  shapers.  An  ad- 
vantage that  is  claimed  for  them  is  the  fact  that  the 
table  and  its  connections  are  under  compression 
rather  than  under  tension.  This  is  somewhat  offset 
by  the  fact  that  the  reverse  is  true  of  the  joints  in 
the  tool  head.  Ordinarily  the  ram  is  operated  by  a 
Whitworth  quick-return  motion,  as  shown  in  Figure 
95  and  96,  or  by  a  ** pillar  drive,"  as  illustrated  in 
P^igure  94.  The  latter  method  is  the  more"  widely  used 
today. 

A  vertical  lever,  or  pillar,  a,  Figure  94,  is  pivoted 


298 


THK  MHciJAMCAI.   KQIIPMKXT 


FIG.   98.      STAXDAKI)  .SIIAPKR 
(f<nil<l  &  Khorhardt. 

feed  on  the  head,  all  the  feeds  are  given  to  the  work- 
holder.  In  the  larger  sizes  of  shaper,  provision  is 
made  for  an  adjustable  support,  d,  which  extends 
from  the  table  to  the  base,  to  preclude  springing  oti 
heavy  cuts.  There  are  various  types  of  shaper di'ives, 
all  of  them  arranged  to  give  a  slow,  powerful  motion 
on  the  forward  stroke  and  a  quick  return.  The  stroke 
may  be  varied  from  zero  up  to  the  full  capacity  of 
tlie  machine,  and   the  ram  may   be  set   forward   or 


PLANHKs.  siiajm^:hs,  SL()TTP:RS 


299 


backwai'd  with  reference  to  the  frame,  so  that  short 
cuts  may  l)e  made  on  different  parts  of  a  piece.  The 
machine  shown  has  the  standard  equipment,  l)ut  spe- 
cial attachments  are  used,  such  as  tilting  and  swivelling 
tables,  which  pei'uiit  the  shaping  of  a  curved  surface, 
and  index  centei's,  somewhat  similar  to  those  that  will 
be  described  in  connection  with  universal  milling  ma- 
chines, which  permit  the  cutting  of  long  spirals.  The 
shaper  is  a  good  tool-room  machine,  and  is  much 
better  for  small  work  than  the  planer.  The  type  of 
drive  used  gives  a  more  accurate  control  of  the 
length  of  stroke  than  can  be  given  by  the  shifting 
belts  used  on  a  planer.  For  accurate  special  work, 
such  as  die-sinking,  it  is  an  advantage  to  have  the 
work  stationarv,  in  order  that  the  action  of  the 
cutting  tool,  when  machining  to  a  line,  may  be 
closelv  watched. 

« 

Construction   and    Operation   of   the    Shaper. — In 

most  shapers,  the  tool  cuts  on  the  stroke  toward  the 
operator.  In  some  types,  however,  this  is  reversed 
and  the  cutting  is  done  on  the  inward  stroke.  The 
latter  types  are  known  as  draw-cut  shapers.  x\n  ad- 
vantage that  is  claimed  for  them  is  the  fact  that  the 
tal)le  and  its  connections  are  under  compression 
inther  than  under  tension.  This  is  somewhat  offset 
l)y  the  fact  that  the  reverse  is  ti'ue  of  the  joints  in 
the  tool  head.  Ordinarily  the  i-am  is  operated  by  a 
Whitworth  quick-return  motion,  as  shown  in  Figure 
!).")  and  !)(),  or  by  a  "pillar  drive,''  as  illustrated  in 
FiiAure  94.  The  iattei*  method  is  the  more  widelv  used 
todav. 

A  vertical  lever,  or  pillar,  a.  Figure  94,  is  piloted 


J 


W) 


i 


PLANERS,  SHAPERS,  SLOTTERS 


301 


at  its  lower  end,  b,  to  the  frame  near  the  floor.  The 
upper  end  is  connected  with  the  ram.  This  lever  os- 
cillates backward  and  forward  about  its  lower  end 
under  the  influence  of  a  crank  pin,  c,  and  sliding 
block,  d,  which  rotate  about  the  shaft,  e.  When  the 
crank  pin  and  the  block  are  turning  forward  on  the 
upper  part  of  their  rotation,  they  are  close  to  the  ram, 
where  they  give  the  slowest  movement  and  exert  the 
greatest  power.  On  the  return  stroke,  they  are  in  the 
lower  half  of  the  rotation  and  closest  to  the  fulcrum, 
b,  of  the  pillar,  and  consequently  give  a  quick  return 
to  the  ram  above.  The  stroke  length  is  varied  by 
turning  the  shaft,  f,  which  screws  the  block,  d,  and 
the  crank  pin,  c,  in  toward  the  center,  thus  reducing 
the  crank  throw.  The  position  of  the  ram  is  changed 
by  loosening  the  clamp,  g,  and  turning  the  screw,  h, 
by  means  of  the  hand-wheel,  i,  which  moves  the  ram 
forward  or  backward  with  reference  to  the  lever,  a. 

The  length  of  the  ram  is  usually  a  little  more  than 
double  the  nominal  size  of  the  machine;  the  length  of 
the  guides  on  the  top  of  the  column  in  which  it  slides, 
is  about  1%  times  the  length  of  the  stroke  of  the  ma- 
chine. Theoretically,  for  the  most  even  wear  these 
should  be  of  the  same  length,  but  practically  this  con- 
dition is  not  necessary,  since  short-stroke  work  is 
kept  back  on  the  table  as  near  the  column  as  pos- 
sible. The  cross-section  of  the  ram  is  substantially 
that  of  an  inverted  letter  U,  as  shown  at  j.  Figure 
94,  with  the  sliding  surfaces  along  the  outer  edge  of 
the  bottom.  The  cross  rail  slides  directly  on  the 
front  face  of  the  upright;  the  table  slides  horizontally 
on  the  cross  rail,  and  is  provided  with  a  transverse 


» 


I 


302 


THE  MECHANICAL  EQUIPMENT 


power-  and  hand-operated  feed.  The  rod  that  oper- 
ates the  power  feeds  is  seen  at  e,  Figure  93,  on  the 
side  of  the  frame. 

The  Traversing  Shaper.— Figure  95  shows  a  trav- 
ersing shaper,  a  type  of  machine  useful  in  finishing 
small  spots  on  large,  long,  and  unwieldy  pieces.  These 
may  be  clamped  to  the  face  along  the  front  of  the 
main  frame  in  place  of  the  tables  shown  in  the  illus- 
tration. The  rams,  a,  of  which  there  are  several, 
are  carried  in  sliding  heads,  b,  which  move  along  the 
guide  on  top  of  the  frame;  each  ram  is  driven  by  a 
Whitworth  quick-return  motion,  shown  in  Figure  96. 
The  large  gears,  c,  c.  Figures  95  and  96,  carrying  the 
crank,  are  driven  from  small  pinions,  d,  d,  on  a  hori- 
zontal shaft  just  behind  the  upper  corner  of  the 
frame.  These  pinions  traverse  sidewise  with  the  slid- 
ing head,  or  carriage,  and  are  eyed  to  this  shaft  with  a 
sliding  key.  The  shaft  is  therefore  able  to  drive  the 
mechanism  of  the  carriage  at  any  position  along  the 
top. 

Figure  96  shows  a  detail  of  the  driving  mechanism. 
The  large  gear,  c,  which  rotates  uniformly,  turns  in 
the  head,  b,  on  the  center,  e.  The  slotted  crank,  f, 
which  drives  the  ram  through  the  pin,  g,  turns  about 
the  center,  h,  which  is  also  fixed  with  respect  to  the 
head,  b.  The  crank,  f,  is  driven  by  a  pin,  i,  fixed  in 
the  gear,  c.  Since  this  pin,  i,  turns  about  e,  its  path 
is  circular,  but  it  is  eccentric  to  the  center,  h,  of  the 
crank.  That  portion  of  the  motion  of  the  pin,  i, 
which  is  above  the  horizontal  line  through  h,  causes 
the  return  motion,  indicated  in  Figure  96  as  the  **arc 
of  return."     The  motion  below  this  horizontal  line, 


^ 


»i 


» 


I 


li 


302 


THE  MECHANICAL  EQUIPMENT 


power-  and  hand-operated  feed.  The  rod  that  oper- 
ates tlie  power  feeds  is  seen  at  e,  Figure  93,  on  thv 
side  of  the  frame. 

The  Traversing  Shaper.— Figure  9r)  sliows  a  trav- 
ersing shaper,  a  type  of  machine  useful  in  iinishing 
small  spots  on  large,  long,  and  unwieldy  pieces.  These 
may  be  clamped  to  the  face  along  the  front  of  the 
main  frame  in  place  of  the  tables  shown  in  the  illus- 
tration. The  rams,  a,  of  which  there  are  several, 
are  carried  in  sliding  heads,  1),  which  move  along  the 
guide  on  top  of  the  frame;  each  ram  is  driven  by  a 
AVhitworth  quick-return  motion,  shown  in  Figure  9(). 
The  large  gears,  c,  c,  Figures  95  and  9(i,  carrving  th(^ 
crank,  are  driven  from  small  pinions,  d,  d,  on  a  hori- 
zontal shaft  just  behind  the  upper  corner  of  the 
frame.  These  pinions  traverse  sidewise  with  the  slid- 
ing head,  or  carriage,  and  are  eyed  to  this  shaft  with  a 
sliding  key.  The  shaft  is  therefore  able  to  drive  the 
mechanism  of  the  carriage  at  any  position  along  the 
top. 

P'igure  96  sIioavs  a  detail  of  the  driving  mechanism. 
The  large  gear,  c,  which  rotates  uniformly,  turns  in 
the  head,  b,  on  the  center,  e.  The  slotted  crank,  f, 
which  drives  the  ram  through  the  pin,  g,  turns  about 
the  center,  h,  which  is  also  fixed  with  respect  to  the 
head,  b.  The  crank,  f,  is  driven  ])y  a  i)in,  i,  iixed  in 
the  gear,  c.  Since  this  pin,  i,  turns  about  e,  its  path 
is  circular,  but  it  is  eccentric  to  the  center,  h,  of  tlir 
crank.  That  portion  of  the  motion  of  the  pin,  i, 
which  is  above  the  horizontal  line  through  h,  cause.< 
the  return  motion,  indicated  in  Figure  9()  as  the  *'ar'' 
of  return."     The  motion   below  this  horizontal   line. 


D5 


m 


gi 


CO 

© 

00 


304 


THE  MECHANICAL  EQUIPMENT 


PLANERS,  SHAPERS,  BLOTTERS 


305 


^ 


FIG.  96.      WHITWORTH  QUICK-RETURN  MOTION 

indicated  as  **arc  of  cut,''  causes  the  forward  mo- 
tion. Since  the  pin  is  moving  at  a  constant  rate,  and 
the  arc  of  return  is  much  shorter  than  the  arc  of  cut, 
the  return  motion  is  made  in  much  less  time  than  the 
forward  motion.  If  the  pin,  g,  is  out  at  the  end  of 
the  crank-slot,  as  at  g'  in  Figure  95,  the  ram  is  tak- 
ing a  full  stroke.  If  it  is  in  close  to  the  center,  the  ram 
is  taking  a  short  one. 

The  base  in  Figure  95  is  shown  equipped  with 
tables;  these  convert  the  machine  into  two  standard 
shapers,  which  may  be  used  for  small  work.  On  the 
floor  is  an  index  center  which  may  be  set  on  the  table 
for  planing  circular  work  along  a  line  parallel  to  its 
axis.  The  table  to  the  right  carries  on  its  upper  face 
a  swiveling  vise,  which  may  be  set  at  any  angle  in  the 


plane  of  the  face  to  which  it  is  clamped.  Since  the 
tables  may  be  swiveled  in  a  vertical  plane,  the  com- 
bination of  the. two  circular  motions  enables  the  shaper 
to  plane  at  any  angle. 

The  Vertical  Shaper,  or  Blotter. — The  slotter,  or 
vertical  shaper.  Figure  97,  is,  as  the  latter  name  im- 
plies, a  shaper  in  which  the  motion  of  the  ram  is 
vertical,  instead  of  horizontal.  On  these  machines  the 
work  is  carried  on  a  slotted,  circular  table,  a,  which 
is  provided  with  a  rotary  feed  operated  by  hand  or 
machine  power.  The  table,  and  its  base,  b,  have  a 
transverse  hand  or  power  feed  on  a  saddle,  c,  which, 
in  turn,  has  a  feed  in  and  out  on  the  main  base  of  the 
machine.  This  combination  of  feeds  permits  the 
shaper  to  cut  faces  at  right  angles  in  two  directions, 
and  also  to  plane  circular  faces.  The  last  is  particu- 
larly useful  in  machining  curved  surfaces  that  have 
a  projection  which  precludes  their  being  turned  on 
a  lathe. 

The  ram  in  this  machine  can  be  tilted  outward  for 
any  angle  from  zero  to  5  degrees,  an  advantage  that 
is  of  particular  value  in  the  cutting  of  tapered  key- 
ways.  Like  the  shaper,  the  ram  is  driven  by  some 
form  of  quick-return  motion.  Any  part  may  be 
clamped  rigidly  to  its  neighbor,  and,  by  a  combina- 
tion of  two  of  the  motions,  oblique  or  irregular  out- 
lines may  be  cut.  It  is  therefore  often  used  for  finish- 
ing the  profiles  of  irregular  pieces. 

Figure  98  shows  a  machine  especially  adapted  for 
key-seating  work.  The  slotter  is  often  used  for  this 
purpose.  The  key  seater  is  a  single-purpose  machine, 
used  for  cutting  the  keyways  on  pulleys,  gears,  and 


il 


PLANERS,  SHAPERS,  SLOTTERS 


307 


PIG.  97.      VERTICAL  SLOTTING  MACHINE 

Pratt  &  Whitney  Co. 

306 


FIG.   98.      KEY-SEATING   MACHINE 
Baker  Bros^ 

SO  on,  which  have  already  been  bored  and  faced.  The 
illustration  shows  a  large  propeller  set  in  place.  The 
cutter,  a,  in  this  machine  is  carried  in  the  round  bar, 

b,  which  extends  up  through  the  hub.  It  is  operated 
by  a  rack-and-pinion  driving  mechanism  located  in 
the  frame  below  and  does  its  work  in  a  draw  cut  on 
the  downward  stroke.  The  cutter  has  a  guide  carried 
by  the  arm  which  extends  forward  from  the  upright, 

c,  at  the  back  of  the  machine. 


I 


PLANKRS.  SllArKKS.  SLoTTKKS 


:>(>: 


FIG.   97.      VKRTICAL  Sr.OTTIX(;    MACHINK 
I'nilf    .V:    WliiliM'V    i\K 


FIG.    98.      KEY-SEATING    MACHINE 
r.ak<'r   r.ros. 

SO  on,  which  have  already  been  bored  and  faced.  The 
illustration  shows  a  large  propeller  set  in  place.  The 
cutter,  a,  in  this  machine  is  carried  in  the  round  bar, 

b,  which  extends  up  through  the  hub.  It  is  operated 
by  a  rack-and-pinion  driving  mechanism  located  in 
the  frame  below  and  does  its  work  in  a  draw  cut  on 
the  downward  stroke.  The  cutter  has  a  guide  carried 
bv  the  arm  which  ext(Mids  forward  from  the  upright, 

c,  at  the  back  of  the  machine. 


MILLING  MACHINES 


309 


CHAPTER  XVIII 
MILLING  MACHINES 

Some  Advantages  of  the  Milling  Process.— The  mill- 
ing cutters,  in  Chapter  XII,  has  grown  steadily  in 
importance  for  the  past  fifty  or  sixty  years.  Profes- 
sor C.  H.  Benjamin*  has  stated  some  of  its  ad- 
vantages as  follows: 

Twenty-five  years  ago  the  milling  machine  was  regarded 
as  a  special  tool,  and  the  bulk  of  straight  work  was  done  on 
the  planer  and  the  shaping;  machine.  Today  the  milling  ma- 
chine is  in  the  lead,  and  is  preferred  by  most  manufacturers 
for  all  work  within  its  range.  The  reason  for  this  is  the 
simple  fact  that  this  machine  will  do  more  work,  or  will  do 
the  same  work  with  a  greater  degree  of  accuracy.  The  mill- 
ing cutter  is  a  multiple  tool  having  many  cutting  edges,  and 
it  has  no  return  motion,  but  cuts  all  the  time.  Furthermore, 
the  possibility  of  shaping  regular  outlines  by  one  operation, 
and  of  repeating  that  operation  and  thus  duplicating  the  pat- 
tern indefinitely,  gives  the  milling  machine  a  great  advantage 
over  machines  using  a  single  point  tool.  Even  in  the  simple 
operation  of  facing  plane  surfaces,  the  milling  cutter  with 
inserted  teeth  has  made  records  which  no  reciprocating  ma- 
chine can  hope  to  equal.  The  fact  that  both  types  of  ma- 
chines are  today  working  side  by  side  in  the  best  shops,  shows 
that  each  is  finding  its  own  proper  field  and  succeeding  in 
that  field. 

The  Work  of  the  Milling  Machine.— The  milling 
machine,  with  the  automatic  lathe,  is  relied  on  to  do 
the  bulk  of  the  work  in  plants  that  are  manufactur- 
ing on  an  interchangeable  basis.    When  first  used  it 


♦Modern  American  Machine  Tools;  C.  H.  Benjamin,  p.  198. 

308 


was  confined  to  light  work,  but  of  recent  years  has 
been  applied  more  and  more  to  larger  and  heavier 
operations.  It  is  used  for  the  simplest  kind  of  repeti- 
tion automatic  work  and,  in  the  form  of  the  universal 
milling  machine,  for  the  most  delicate  and  skilful 
operations.  The  universal  milling  machine  is  the 
most  characteristic  machine  in  the  tool  room.  For 
manufacturing  purposes,  the  milling  process  is  used 
mainly  for  producing  large  quantities,  as  the  tools  are 
comparatively  expensive,  require  skill  in  setting,  and 
are  more  restricted  in  their  use  than  lathe  tools.  On 
the  other  hand,  accurate  milling  operations  can  be 
performed  by  comparatively  cheap  labor,  the  wear 
on  the  cutters  is  slow,  and  a  great  many  kinds  of  cuts 
may  be  taken  which  would  be  difficult  to  produce 
commercially  in  any  other  way.  Some  idea  of  the 
variety  of  cuts  that  it  is  possible  to  make  may  be 
gathered  from  the  collection  of  milling  cutters  shown 
in  Figure  99. 

Origin  and  Development  of  Milling  Machine.— Prob- 
ably the  first  milling  machine  ever  built — certainly 
the  oldest  now  in  existence — is  at  present  in  the 
museum  of  the  Sheffield  Scientific  School  of  Yale  Uni- 
versity. It  was  built  by  Eli  Whitney  some  time  before 
1818,  and  was  used  for  the  manufacture  of  gun  parts 
for  the  United  States  Government.  This  machine  is  a 
very  simple  affair  and  could  never  have  been  used  for 
anything  but  light,  straight  cuts.  The  '*  lineal  descend- 
ant" of  this  machine  embodying  the  same  general  ar- 
rangement but  greatly  refined  in  design,  of  course,  is 
the  hand  milling  machine  shown  in  Figure  100.  It 
has  a  box-shaped  body,  and  a  head  somewhat  sim- 


,f 


t 


ii 


^ 


MILLING  MACHINES 


311 


'    ■'      **     -    •        -       ■    -■* ■*JI        L      m.M    ll1iW.ll      ■      1..JI,, 9 


ilar  to  a  lathe  headstock,  which  is  cast  integral  with 
it.  This  head  carries  a  spindle,  which  is  driven  hy 
a  stepped  cone  pulley.  The  small  end  of  the  pulley  is 
toward  the  front  bearing,  as  this  position  permits  a 
firmer  bracing  for  the  front  bearing,  which  takes  the 
end  thrust.  The  front  of  the  column  is  provided 
with  vertical  ways,  and  carries  the  knee,  a.  The  up- 
and-down  motion  of  the  knee  is  operated  by  the 
handle,  b,  and  a  rack  and  pinion,  which  does  not 
show. 

Adjustable  stops  are  provided  on  the  side  of  the 
guide,  as  shown,  which  limit  the  motion  as  may  be 
desired.  On  the  top  of  the  knee  is  a  saddle,  c,  which 
may  be  moved  in  and  out  from  the  frame  of  the 
machine  by  the  adjustable  screw,  d,  and  clamped  in 
any  position.  On  the  saddle  is  the  table,  e,  which 
has  a  transverse  movement  under  the  milling  cutter, 
operated  through  the  hand  lever,  f,  and  the  pinion 
and  rack,  as  clearly  shown.  The  table  is  slotted  to 
carry  a  standard  milling-machine  vise  or  special  fix- 
ture to  hold  the  work. 

In  operating  the  machine,  the  attendant  sets  the 
work  in  the  jaws,  raises  the  knee  and  the  table  by 
the  handle,  b,  to  a  point  determined  by  the  side  stop, 
and  then  feeds  the  work  horizontally  with  the  other 
handle,  f ,  to  a  definite  point  set  by  the  stop,  g,  at  the 
front  of  the  table.  The  weight  of  the  knee  and  the 
table  is  counterbalanced  by  a  weight  within  the 
column,  so  that  the  operator  does  not  have  to  lift 
them  at  each  operation.  These  machines  are  adapted 
to  milling  the  small  parts  of  guns,  sewing  machines, 
typewriters,  and  the  like. 


•■1 

,  ,■•11  , 


4     i  I 


MILLING  MACHINES 


:]U 


ilar  to  a  lathe  lieadstock,  Avliieh  is  east  integral  with 
it.  This  head  carries  a  spindle,  which  is  driven  by 
a  stepped  cone  pulley.  The  small  end  of  the  pulley  is 
toward  the  front  bearing,  as  this  position  permits  a 
firmer  bracing  for  the  front  bearing,  which  takes  the 
end  thrust.  The  front  of  the  column  is  provided 
with  vertical  ways,  and  carries  the  knee,  a.  The  up- 
and-down  motion  of  the  knee  is  operated  by  the 
liandle,  b,  and  a  rack  and  pinion,  which  does  not 
show. 

Adjustable  stops  are  provided  on  the  side  of  the 
guide,  as  shown,  which  limit  the  motion  as  may  be 
desired.  On  the  top  of  the  knee  is  a  saddle,  c,  which 
may  be  moved  in  and  out  from  the  frame  of  the 
machine  by  the  adjustable  screw,  d,  and  clamped  in 
any  position.  On  the  saddle  is  the  table,  e,  which 
has  a  transverse  movement  under  the  milling  cutter, 
operated  through  the  hand  lever,  f,  and  the  pinion 
and  rack,  as  clearly  shown.  The  table  is  slotted  to 
carry  a  standard  milling-machine  vise  or  special  fix- 
ture to  hold  the  work. 

In  operating  the  machine,  the  attendant  sets  the 
work  in  the  jaws,  raises  the  knee  and  the  table  by 
the  handle,  b,  to  a  point  determined  by  the  side  stop, 
and  then  feeds  the  work  horizontally  with  the  other 
handle,  f,  to  a  definite  point  set  by  the  stop,  g,  at  the 
front  of  the  table.  The  weight  of  the  knee  and  the 
table  is  counterbalanced  by  a  weight  within  the 
column,  so  that  the  operator  does  not  have  to  lift 
them  at  each  operation.  These  machines  are  adapted 
to  milling  the  small  parts  of  guns,  sewing  nincliiiies, 
typewriters,  and  the  like. 


i 


MILLING  MACHINES 


313 


The  Lincoln  Type.— About  1850,  F.  W.  Howe  and 
R.  S.  Lawrence,  of  Robbins  and  Lawrence,  Windsor, 
Vermont,  designed  a  miller  which  was  the  forerunner 
of  the  Lincoln  milling  machine,  shown  in  Figure  lOL 
They  brought  this  to  Hartford,  and  fifty  machines  of 
the  same  general  design  were  ordered  from  the  Lin- 
coln Iron  Works  of  that  city  for  the  Colt  Armory, 
which  was  erected  in  1855.  The  machines  were  built 
under  the  direction  of  F.  A.  Pratt  and  Amos  Whitney, 
who  later  formed  the  firm  of  Pratt  and  Whitney.  Mr. 
Pratt  added  certain  improvements — such  as  the  screw 
drive  for  the  main  table  feed — and  various  details. 
Many  thousand  machines  of  this  design  have  been 
built  since  that  time;  they  are  known,  even  in  Europe, 
as  the  Lincoln  type  of  miller,  from  the  name  of  the 
builders  of  the  early  machines. 

The  Lincoln  miller  consists  of  a  short,  stiff  bed, 
with  a  headstock,  a,  either  cast  or  bolted  to  it,  which 
carries  a  live  spindle,  b,  and  its  driving  mechanism. 
At  the  other  end  of  the  machine  is  an  upright,  c, 
which  carries  an  adjustable  block,  d,  supporting  the 
outboard  end  of  the  arbor  that  carries  the  milling 
cutters.  The  spindle  and  the  block  are  adjustable 
vertically,  and  accommodate  work  of  different 
heights.  The  work  is  held  in  a  jaw,  e,  or  special 
milling  fixture,  which  is  clamped  to  the  movable  table 
between  the  headstock  and  the  outboard  guide.  The 
upright,  c,  and  the  saddle,  f,  carrying  the  table  are 
adjustable  lengthwise  ^p  w?i^'^  at  the  top  of  the  bed. 
The   saddle   has   no    Tr  .  iiis    direction    but   is 

clamped  to  the  bed  when  set  in  the  desired  position. 

The  table  has  a  cross  feed  operated  by  hand  or 


I; 

'/mi 


f 


MTlJ.lXf!   ArA(  IIIXES 


313 


The  Lincoln  Type.-  About  18:)(),  K.  \V.  Jlowc  mid 
R.  S.  LawiTiieo,  of  Hobbins  and  Ijuwronco,  Windsor, 
Vermont,  dosi<»'iUMl  a  inillcM*  whicb  was  tlic  forerunner 
of  the  Lincoln  milling  machine,  shown  in  Figure  101. 
They  ])rought  tliis  to  Hartford,  and  iifty  machines  of 
the  same  general  design  were  ordered  from  the  Lin- 
coln li'on  AVorks  of  that  eitv  for  the  Colt  Armory, 
which  was  erected  in  185.").  The  machines  were  built 
imder  the  direction  of  F.  A.  Pratt  and  Amos  Whitney, 
wlio  later  foi-med  the  firm  of  Pratt  and  AVhitney.  Mr. 
Pratt  added  certain  improvements — snch  as  the  scre\v 
drive  for  the  main  tal)le  feed — and  various  details. 
Many  thousand  machines  of  this  design  have  been 
built  since  that  time;  they  are  known,  even  in  Europe, 
as  the  Lincoln  type  of  miller,  from  the  name  of  the 
builders  of  the  early  machines. 

TIk'  Lincoln  miller  consists  of  a  short,  stiff  bed, 
with  a  headstock,  a,  either  cast  oi*  bolted  to  it,  which 
carries  a  live  spindle,  b,  and  its  driving  mechanism. 
At  the  other  end  of  the  machine  is  an  upright,  c, 
which  carries  an  adjustable  block,  d,  supporting  the 
outboard  end  of  the  arbor  that  carries  the  milling 
cutters.  The  spindle  and  the  block  are  adjustable 
vertically,  and  acconnnodatc  work  of  different 
heights.  The  work  is  held  in  a  jaw%  e,  or  special 
milling  fixture,  which  is  clamped  to  the  movable  table 
between  the  headstock  and  the  outl)oard  guide.  The 
upright,  c,  and  the  saddle,  f,  carrying  the  table  are 
adjustable  lengthwise    -»>  -  'f  the  top  of  the  be<l. 

The    saddle    has    no  .      dii\M'tion    but    is 

^'lamped  to  the  bed  when  set  in  the  desired  position. 
The   table   has  a   cross   h^ed   o])ei-at(Hl   by   hand   or 


r\^\ 


314 


THE  MECHANICAL  EQUIPMENT 


^li 


S- 


power,  which  moves  the  work  under  the  milling 
cutter.  In  the  very  early  machines,  this  was  operated 
by  a  pinion  and  a  toothed  rack  on  the  under  side  of 
the  table.  This  arrangement  caused  the  feed  to  chat- 
ter badly  under  heavy  cuts.  One  of  the  chief  im- 
provements made  by  Mr.  Pratt  was  the  substitution 
of  a  screw  feed,  g,  which  operates  through  a  nut  se- 
cured to  the  saddle.  While  seemingly  a  minor  im- 
provement, it  really  made  the  success  of  the  machine. 
This  type  of  miller  is  used  for  straight  milling  cuts 
on  repetition  work.  It  resembles  in  many  respects 
the  horizontal  boring  machine  shown  in  Figure  75 — in 
fact,  in  many  instances  the  same  operations  may  be 
performed  on  either  machine.  The  spindle,  b,  on  the 
Lincoln  miller,  however,  has  no  traverse  motion,  and 
the  only  feed  of  the  table  is  across  the  machine.  Its 
use  is  therefore  confined  to  operations  that  can  be 
performed  by  a  single  pass  of  the  work  under  the 
cutting  tool — ^but  it  is  remarkable  how  much  can  be 
done  in  this  way.  The  simplicity  of  the  machine  is 
an  element  of  accuracy  and  permits  of  its  operation 
by  unskilled  attendants. 

The  Brings'  Type. — Figure  102  shows  a  machine 
for  the  same  kind  of  work  as  the  above,  in  which  the 
vertical  adjustment  is  in  the  table  instead  of  in  the 
spindle.  In  this  machine  the  frame  consists  of  two 
uprights  cast  together  at  top  and  bottom.  Between 
these,  carried  by  the  guideways,  a,  is  a  saddle,  b, 
which  may  be  adjusted  vertically  by  the  screw,  c, 
underneath.  This  in  turn  carries  a  slotted  table 
which  moves  in  and  out  under  hand  or  power  feed,  as 
in  the  Lincoln  miller.    The  cutter  arbor,  d,  is  fixed 


,^ 


V 


314 


THE  MECHANICAL  EQUIPMENT 


power,    which    moves    llio    work    under    the    milling 
cutter.    In  the  very  early  machines,  this  was  operated 
by  a  pinion  and  a  toothed  rack  on  the  under  side  of 
the  table.    This  arrangement  caused  the  feed  to  chat- 
ter badly  under  heavy  cuts.     One  of  the  chief  im- 
provements made  by  Mr.  Pratt  was  the  substitution 
of  a  screw  feed,  g,  which  operates  through  a  nut  se- 
cured to  the  saddle.     AVhile  seemingly  a  minor  im- 
provement, it  really  made  the  success  of  the  machine. 
This  type  of  miller  is  used  for  straight  milling  cuts 
on  repetition  work.     It  resembles  in  many  respects 
the  horizontal  boring  machine  shown  in  Figure  75 — in 
fact,  in  many  instances  the  same  operations  may  be 
performed  on  either  machine.    The  spindle,  b,  on  the 
Lincoln  miller,  however,  has  no  traverse  motion,  and 
the  only  feed  of  the  table  is  across  the  machine.    Its 
use  is  therefore  confined  to  operations  that  can  be 
performed  by  a  single  pass  of  the  work  under  the 
cutting  tool — but  it  is  remarkal)le  how  much  can  be 
done  in  this  way.     The  simplicity  of  the  machine  is 
an  element  of  accuracy  and  permits  of  its  operation 
by  unskilled  attendants. 

The  Brig^g^s'  Type.— Figure  102  shows  a  machine 
for  the  same  kind  of  work  as  the  above,  in  which  the 
vertical  adjustment  is  in  the  table  instead  of  in  the 
spindle.  In  this  machine  the  frame  consists  of  two 
uprights  cast  together  at  top  and  bottom.  Between 
these,  carried  by  the  guideways,  a,  is  a  saddle,  h, 
which  may  be  adjusted  vertically  by  the  screw,  c, 
underneath.  This  in  turn  carries  a  slotted  table 
which  moves  in  and  out  under  hand  or  power  feed,  .' 
in  the  Lincoln  miller.     The  cutter  arbor,  d,  is  fixe-i 


'■.^ 

|B           ^^L— __^''^   ^^i^^H 

m      W 

II 

11                ^ 

1             *  *-           1 

B^^^^^^^^^^yw^^^^BI 

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^p ' 

••P4 
< 

^^       mm 


^ 

^ 


316 


THE  MECHANICAL  EQUIPMENT 


MILLING  MACHINES 


317 


in  position;  the  support  for  the  outer  end  is  a  bronze 
sleeve  in  the  removable  bushing,  e,  which  is  held  in 
the  frame  by  an  expanding  belt,  f .  The  space  in  the 
base  below  is  used  as  a  tank  for  cutting  lubricant. 

Modem  Development  of  Lincoln  Miller. — Figure  103 
shows  a  modern  development  of  the  Lincoln  Miller. 
It  is  an  automatic  machine  of  heavy  construction 
throughout.  The  uprights  carrying  the  spindle  and 
the  arbor  support  are  parabolic  in  outline,  and  some- 
what resemble  the  uprights  of  a  planer;  the  strain 
to  which  they  are  subject,  in  both  machines,  is  very 
similar  in  nature.  The  various  motions  on  the  ma- 
chine may  be  operated  by  the  hand  levers  in  front; 
in  regular  operation,  however,  they  are  automatic, 
and  are  controlled  by  the  circular  plate  shown  at  the 
front  of  the  machine.  Adjustable  dogs,  a,  may  be  set 
in  position  around  the  edge  of  this  plate,  to  throw  in 
and  out  the  levers  that  control  the  reverse  and  feed 
mechanism.  The  work  starts  from  a  position  well  to 
the  front — where  the  fixture  may  be  loaded  without 
danger  of  injuring  the  hands  of  the  operator — and 
approaches  the  cutter  with  a  rapid  forward  traverse. 
Just  before  the  work  engages  the  cutter,  the  slow 
feed  is  automatically  thrown  in. 

After  the  milling  operation  has  been  completed,  the 
table  is  automatically  returned  quickly  to  its  original 
position,  stops  at  the  end  of  the  motion,  and  waits 
for  the  operator  to  load  the  fixture  and  start  the  for- 
ward feed.  As  the  table  starts  on  the  return  traverse, 
it  is  dropped  somewhat  to  permit  the  work  to  clear 
the  cutter  as  the  table  goes  back;  this  precaution 
prevents  any  marring  of  the  finished  surface.    Then, 


as  the  table  approaches  the  end  of  the  return  travel, 
it  is  automatically  elevated  to  its  cutting  position  and 
remains  at  this  height  during  the  cutting  traverse. 
Because  the  control  of  these  motions  is  entirely  auto- 
matic, one  operator  can  attend  to  several  machines. 
The  cutting  feeds,  by  means  of  change  gears,  may  be 
varied  to  suit  the  requirements,  and  the  table  feeds 
are  entirely  independent  of  the  spindle  speeds. 

Column-and-Knee  Type.— The  plain  miller  of  the 
column-and-knee  type.  Figure  104,  is  a  refinement 
of  the  hand  miller,  and  is  usually  much  larger  and 
equipped  with  power  feeds  in  all  directions.  It  is 
more  flexible  than  the  Lincoln  miller,  as  the  table 
has  not  only  a  transverse  feed,  but  a  vertical  and  an 
in-and-out  motion.  Some  of  these  machines  have 
both  hand  and  power  feeds  for  all  three  of  these 
movements;  some,  for  the  longitudinal  and  transverse 
movements  only;  the  vertical  motion  is  operated  by 
hand;  in  still  others,  only  the  longitudinal  feed  is 
power-driven.  Figure  105  shows  a  vertical  section  of 
another  machine  of  the  same  type.  Clamps  are  pro- 
vided for  locking  the  knee,  a,  to  the  main  frame,  the 
saddle,  b,  to  the  knee,  and  the  table,  c,  to  the  saddle, 
when  motion  at  any  of  these  points  is  not  required. 
A  heavy  bar,  d,  at  the  top  of  the  machine  can  be 
adjusted  in  and  out,  according  to  the  demands  of  the 
work.  This  bar  carries  an  outboard  support  for  the 
milling  arbor,  and  is  itself  stiffened  by  braces,  e,  ex- 
tending from  the  outer  end  down  to  the  end  of  the 

knee. 

Modern  machines  of  this  type  are   driven  by  a 
single-speed  pulley,  and  the  speed  variations  are  ob- 


m\A 


•  ki 


i 
r 


o 
55 


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a 


o 


o 


MILLING  MACHINES 


319 


tained  by  means  of  change  gears.  All  the  feed  move- 
ments are  power-operated,  and  are  provided  with 
stops  to  limit  the  motion.  The  sectional  view  shows 
the  method  of  lubrication  by  which  the  bearing 
lubricant  stored  in  the  reservoir,  A,  is  pumped  to  the 
top  of  the  machine,  where  it  is  distributed  through 
a  perforated  pipe,  f.  The  cutting  lubricant  is  stored 
in  the  reservoir,  C,  is  pumped  to  the  top  of  the  ma- 
chine, and  from  there  is  distributed  over  the  cutters 
and  the  work  through  adjustable  nozzles,  g.  Then  it 
is  returned  to  the  reservoir,  B.  The  latter  acts  as  a 
settling  tank  for  the  chips,  which  sink  to  the  bottom; 
the  lubricant  runs  over  the  top  of  the  partition  into 
the  reservoir,  C. 

Vertical  Miller.— The  vertical  type  of  plain  miller 
is  in  many  ways  similar  to  the  column-and-knee  type, 
so  far  as  the  arrangements  of  the  table  are  con- 
cerned. The  spindle,  however,  stands  in  a  vertical 
position,  instead  of  being  horizontal.  It  may  be 
carried  in  a  head,  adjustable  with  respect  to  the  main 
body  of  the  machine,  as  shown  in  Figure  106,  or  the 
head  may  be  cast  solid  with  the  frame.  The  vertical 
type  of  machine  clearly  embodies  the  principles  of 
the  drilling  machine.  The  spindle  and  the  table 
are  similarly  located,  and  the  cutter  is  mounted  on 
the  lower  end  of  the  spindle.  The  table,  however, 
has  a  series  of  movements  not  found  on  the  drilling 
machine. 

For  such  work  as  face  milling,  die-sinking  and 
the  cutting  of  profiles,  the  vertical-spindle  machine 
has  many  advantages  as  compared  with  the  horizontal 
type.    In  many  cases  a  piece  mav  be  fastened  directlv 


II 


ill 


If 


w 

O 


o  H 

w  E 

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o  ^ 

o  P, 

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o  = 


MILLING  MACHINES 


319 


o 


o 


tained  by  means  of  change  gears.  All  the  feed  move- 
ments are  power-operated,  and  are  provided  with 
stops  to  limit  the  motion.  The  sectional  view  shows 
the  method  of  lubrication  by  which  the  bearing 
lubricant  stored  in  the  reservoir,  A,  is  pumped  to  the 
top  of  the  machine,  where  it  is  distributed  through 
a  perforated  pipe,  f.  The  cutting  lubricant  is  stored 
in  the  reservoir,  C,  is  pumped  to  the  top  of  the  ma- 
cliine,  and  from  there  is  distributed  over  the  cutters 
and  the  work  through  adjustable  nozzles,  g.  Then  it 
is  returned  to  the  reservoir,  B.  The  latter  acts  as  a 
settling  tank  for  the  chips,  which  sink  to  the  bottom; 
the  lubricant  runs  over  the  top  of  the  partition  into 
the  reservoir,  C. 

Vertical  Miller.— The  vertical  type  of  plain  miller 
is  in  many  ways  similar  to  the  column-and-knee  type, 
so  far  as  the  arrangements  of  the  table  are  con- 
cerned. The  spindle,  however,  stands  in  a  vertical 
position,  instead  of  being  horizontal.  Tt  may  be 
carried  in  a  head,  adjustable  with  respect  to  the  main 
l)ody  of  the  machine,  as  shown  in  Figure  lOG,  or  the 
head  may  be  cast  solid  with  the  frame.  The  vertical 
type  of  machine  clearly  embodies  the  principles  of 
the  drilling  machine.  The  spindle  and  the  table 
are  similarly  located,  and  the  cutter  is  mounted  on 
the  lower  end  of  the  spindle.  The  table,  however, 
has  a  series  of  movements  not  found  on  the  drilling 
machine. 

For  such  work  as  face  milling,  die-sinking  and 
iiie  cutting  of  profiles,  the  vertical-spindle  machine 
fias  many  advantages  as  compai-ed  with  the  horizontal 
type.     In  many  cases  a  pieee  may  be  fastened  directly 


16 

t-H 

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CJ     OJ 

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MILLING  MACHINES 


321 


to  the  top  of  the  table,  whereas  fixtures  would  be 
necessary  if  the  work  were  done  on  a  horizontal  ma- 
chine. Also,  the  operator  can  see  his  work  at  all 
times,  and  can  follow  any  irregularities  of  outline 
much  more  readily  than  when  he  uses  the  horizontal 
type. 

The  die-sinker,  Figure  107,  is  a  type  of  vertical 
milling  machine  especially  adapted  to  the  purpose 
indicated  by  its  name.  The  dies  are  clamped  in  the 
jaws  on  the  table,  and  a  small  end  mill,  formed  or 
plain  as  the  case  may  be,  is  carried  in  the  lower  end 
of  the  spindle.  Longitudinal,  transverse  and  vertical 
movements,  as  well  as  horizontal  rotation,  may  be 
given  to  the  work.  Frequently  a  swiveling  vise  is 
used,  which  permits  of  angular  adjustments  in  a 
vertical  plane  as  well.  These  feeds  are  operated  only 
by  hand,  as  this  type  of  machine  is  used  by  skilled 
tool  makers  who  follow  the  outline  laid  out  on  the  sur- 
face of  the  die,  and  scarcely  any  two  jobs  are  the 
same.  Power  feeds  would  therefore  be  almost  use- 
less. As  the  cuts  used  in  die-sinking  are  almost  in- 
variably light,  the  spindle  is  driven  directly,  with 
gearing,  by  a  half-turn  belt  from  the  cone  pulley  be- 
low. 

The  heavier  type  of  machine,  shown  in  Figure  106, 
is  used  for  manufacturing  purposes;  it  is  provided 
with  a  powerful  drive  that  has  the  necessary  speed 
changes,  and  so  on.  Frequently  machines  of  this 
type  are  provided  with  a  circular  table  that  has  a 
rotary  power  feed.  Figure  106  shows  such  a  set-up — 
the  heavy  face-milling  cutter  is  machining  the  bot- 
toms of  flatirons,  which  are  arranged  around  the  top 


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1()  llic  lop  of  tli(*  1a])l(%  wliorcas  fixtures  would  l)o 
iHH't'ssarv  if  I  he  work  whm'c  done  on  a  liori/onlal  nia- 
eliino.  Also,  tlio  operator  can  see  liis  work  at  all 
times,  and  cau  follow  any  irregularities  of  outline 
much  more  readilv  than  when  he  uses  the  horizontal 

The  die-sinker,  Figure  107,  is  a  type  of  vertical 
milling  machine  especially  adapted  to  the  purpose 
indicatiMl  by  its  name.  Tln^  dies  are  clamped  in  the 
jaws  on  the  table,  and  a  small  end  mill,  formed  or 
plain  as  the  case  may  he,  is  carried  in  the  lower  end 
of  the  spindle.  Longitudinal,  transverse  and  vertical 
movements,  as  well  as  horizontal  rotation,  may  he 
given  to  the  work.  Frequently  a  swiveling  vise  is 
used,  which  permits  of  angular  adjustments  in  a 
vertical  plane  as  well.  These  feeds  are  operated  only 
hy  hand,  as  this  type  of  machine  is  used  by  skilled 
tool  makers  who  follow  the  outline  laid  out  on  the  sur- 
face of  the  die,  and  scarciOv  anv  two  iobs  are  the 
same.  Power  feeds  would  therefore  be  almost  use- 
less. As  the  cuts  nsed  in  die-sinking  are  almost  in- 
variably light,  the  spindle  is  driven  directly,  with 
gearing,  l)y  a  half-turn  belt  from  the  cone  pulley  be- 
low. 

The  heavier  type  of  machine,  shown  in  Figure  106, 
is  used  for  mamifacturing  purposes;  it  is  provided 
with  a  powerful  drive  that  has  the  necessary  speed 
changes,  and  so  on.  Frequently  machines  of  this 
type  are  provided  with  a  circular  table  that  has  a 
rotary  power  W'od.  Figure  lOfi  shows  su(*h  a  set-up — 
the  heavy  face-milling  cutter  is  machining  the  ])ot- 
toms  of  flatirons,  which  are  arranged  around  the  to]) 


322 


THE  MECHANICAL  EQUIPMENT 


of  a  fixture  and  given  a  continuous  feed.  As  the  feed- 
ing motion  is  comparatively  slow,  the  finished  work 
may  be  taken  out  and  new  pieces  may  be  substituted 
while  the  cutting  is  going  on.  The  work  of  the  ma- 
chine is  therefore  continuous. 

Profile  Milling  Machine.— By  giving  the*  milling 
cutter  some  desired  contour,  and  moving  the  work 
past  it  in  the  necessary  irregular  path,  very  irregular 
surfaces  may  be  cut.  When  such  surfaces  are  to  be 
produced  on  a  manufacturing  basis,  the  profile  mill- 
ing machine,  shown  in  Figure  108,  is  used.  In  this 
machine  the  cutting  tool  is  inserted  in  the  end  of 
the  spindle,  at  a,  and  a  hardened  steel  guide  pin  is 
clamped  into  the  head  at  b  or  b'.  As  a  part  of  the 
fixture— holding  the  work,  and  at  one  side  of  it— is 
a  former  plate,  which  has  a  shape  similar  to  that  of 
the  piece  to  be  milled.  By  operating  the  handle,  c, 
which  moves  the  table  in  and  out,  and  the  handle,  d, 
which  moves  the  head  sidewise,  the  operator  causes 
the  pin,  b,  to  follow  the  curved  edge  of  this 
**former."  The  work,  accordingly,  moves  past  the 
cutter  in  the  irregular  path  required. 

Figure  109  shows  the  frame  of  an  automatic  pistol 
that  contains  several  cuts  of  this  nature.  A  formed 
milling  cutter  is  used  which  has  a  concave  outline  of 
the  same  curve  as  the  edge.  The  work  is  fed  so  that 
the  cutter  moves  along  the  piece  from  a,  around  the 
outside  of  the  finger  loop,  and  down  the  handle  to  b. 
It  may  then  be  guided  around  to  the  back  of  the 
handle,  along  it,  and  off  the  work  at  c.  The  former 
plate  which  guides  this  cut  will  have  a  shape  similar 
to  the  path  of  the  milling  cutter  around  the  stock. 


MILLING  MACHINES 


323 


FIG.    109.      AN  EXAMPLE  OF  PROFILING  WORK 

A  second  and  smaller  cut,  of  a  similar  nature,  is 
shown  on  the  side  of  the  frame  from  d  to  e;  there  is, 
of  course,  a  corresponding  one  on  the  opposite  side. 
A  third  profiling  cut  will  be  made  around  the  inside 
of  the  finger  loop,  which  is  still  rough  on  the  piece 
shown. 

Almost  any  contour  can  be  given  to  the  milling  cut- 
ter, and  it  can  be  made  to  travel  in  almost  any  path 
— the  only  condition  is  that  the  radius  of  the  curved 
surface  in  corners,  such  as  f  and  f ,  must  be  less  than 
the  radius  of  the  milling  cutter.  For  internal  cuts, 
such  as  the  one  inside  of  the  finger  loop,  provision  is 
made  for  lifting  the  guide  pin  and  cutter,  by  means 
of  the  lever,  e,  above  the  plane  of  the  work  and  the 
**former",  and  dropping  them  down  again  to  the 
zone  in  which  the  cut  is  to  be  made. 

Frequently  profiling  machines  are  made  in  which 
the  upper  rail  is  longer  and  carries  an  additional 
head  and  spindle  with  its  own  guide  pin.    One  of  the 


"  »i 


)( 


322 


THE  xMECHAiMCAL  EQUIPMEJST 


of  a  fixture  and  given  a  continuous  feed.  As  tlie  feed- 
ing motion  is  comparatively  slow,  the  finished  work 
may  be  taken  out  and  new  pieces  may  be  substituted 
while  the  cutting  is  going  on.  The  work  of  the  ma- 
chine is  therefore  continuous. 

Profile  Milling:  Machine.— By  giving  the  milling 
cutter  some  desired  contour,  and  moving  the  work 
past  it  in  the  necessary  irregular  path,  very  irregular 
surfaces  may  be  cut.  When  such  surfaces  are  to  be 
produced  on  a  manufacturing  basis,  the  profile  mill- 
ing machine,  shown  in  V'lgure  108,  is  used.  In  this 
machine  the  cutting  tool  is  inserted  in  the  end  of 
the  spindle,  at  a,  and  a  hardened  steel  guide  pin  is 
clamped  into  the  head  at  b  or  b'.  As  a  part  of  the 
fixture— holding  the  work,  and  at  one  side  of  it— is 
a  former  plate,  which  has  a  shape  similar  to  tliat  of 
the  piece  to  be  milled.  By  operating  the  handle,  c, 
which  moves  the  table  in  and  out,  and  the  handle,  d, 
which  moves  the  head  sidewise,  the  operator  causes 
the  pin,  b,  to  follow  the  curved  edge  of  this 
**former."  The  work,  accordingly,  moves  past  the 
cutter  in  the  irregular  path  required. 

Figure  109  shows  the  frame  of  an  automatic  pistol 
that  contains  several  cuts  of  this  nature.  A  formed 
milling  cutter  is  used  which  has  a  concave  outline  of 
the  same  curve  as  the  edge.  The  work  is  fed  so  that 
the  cutter  moves  along  the  piece  from  a,  around  the 
outside  of  the  finger  loop,  and  down  the  handle  to  b. 
It  may  then  be  guided  around  to  the  back  of  the 
handle,  along  it,  and  off  the  work  at  c.  The  former 
plate  which  guides  this  cut  will  have  a  shape  similar 
to  the  path  of  the  milling  cutter  around  the  stock. 


M1LIJX(;  AFACIIINKS 


.».).» 
•>-•> 


FIG.    109.      AX   EXAMl'Li:   OF   PROFILING    WORK 


A  second  and  smaller  cut,  of  a  similar  nature,  is 
shown  on  the  side  of  the  frame  from  d  to  e;  there  is, 
of  course,  a  corresponding  one  on  the  opposite  side. 
A  third  profiling  cut  will  be  made  around  the  inside 
of  the  finger  loop,  which  is  still  rough  on  the  piece 
shown. 

Almost  any  contour  can  be  given  to  the  milling  cut- 
ter, and  it  can  be  made  to  travel  in  almost  any  path 
— the  only  condition  is  that  the  radius  of  the  curved 
sui-face  in  corners,  such  as  f  and  f ,  must  be  less  than 
the  radius  of  the  milling  cutter.  P^'or  internal  cuts, 
such  as  the  one  inside  of  the  finger  loop,  provision  is 
made  for  lifting  the  guide  pin  and  cutter,  by  means 
of  the  lever,  e,  above  the  plane  of  the  work  and  the 
** former",  and  dropping  them  down  again  to  the 
zone  in  which  the  cut  is  to  be  made. 

Frequently  profiling  machines  are  made  in  which 
the  upper  rail  is  longer  and  carries  an  additional 
head  and  spindle  with  its  own  guide  pin.    One  of  the 


[Ill 


324  THE  MECHANICAL  EQUIPMENT 

heads  is  used  for  a  roughing  cut,  and  the  other  for  a 
finishing  cut.  Both  are  made  in  one  setting  of 
the  piece,  finishing  it  ajccurately  to  dimensions;  thus 
hand  fitting  is  done  away  with.  It  is  obvious  that 
this  type  of  machine  can  produce  interchangeably 
and  on  a  manufacturing  basis,  some  very  irregular 
shapes. 

Universal  Milling  Machine.— The  aristocrat  among 
nulling  machines,  and  in  fact  in  the  whole  field  of 
machine  tools,  is  the  universal  milling  machine,  one 
of  which  is  shown  in  Figure  110.  There  is  scarcely 
a  type  of  cut  known  in  the  machine  shop  which  can- 
not be  made  on  this  machine.  It  was  first  developed 
by  Brown  &  Sharpe  in  1861,  for  milling  the  flutes 
of  a  twist  drill.  The  machine  has  the  column,  knee, 
and  saddle  of  the  type  shown  in  Figure  104.  The 
'  table,  a,  however,  is  arranged  to  swivel  horizontally 
through  a  very  considerable  angle,  and  is  provided 
with  an  accurately  graduated  measuring  circle,  b. 

On  the  table  is  a  so-called  universal  head,  H,  shown 
in  Figures  110,  111,  and  112.  This  head  corresponds 
in  some  ways  to  the  head-stock  of  the  lathe,  although 
it  is  wholly  different  in  design.  The  adjustable 
bracket,  c,  which  supports  the  outboard  end  of  the 
work,  corresponds  in  function  to  the  lathe  tail-stock, 
and  the  table  of  the  machine  to  the  lathe  bed.  In  a 
lathe  the  work  revolves  under  the  tool,  and  the  tool  is 
fed  past  the  work.  In  this  case  the  milling  cutter 
revolves,  and  the  work,  carried  on  the  two  centers,  d 
and  e,  may  be  set  at  an  angle  with  reference  to  the 
cutter  and  fed  past  it  or  rotated— or  these  two  mo- 
tions may  be  used  simultaneously. 


FIG.   110.      UNIVERSAL  MILLING  MACHINE 

325 


I 


.V 


M 


If* 


324 


THE  MECHAXICAL  KQUIPMExNT 


heads  is  used  lor  a  lougliino  cut,  and  tlir  oHut  for  a 
finisJiiiig-  cut.  Both  aiv  made  in  one  scttin-  of 
the  piece,  iinishing  it  aiceiirately  to  dimensioiis;  "thus 
liand  fitting-  is  done  away  witli.  It  is  obvious  that 
this  type  of  machine  can  produce  interchangeably 
and  on  a  manufacturing  basis,  some  very  irreonhiV 
shapes. 

Universal  Milling  Machine.— The  ai-istociat  amon- 
mdhng  macliines,  and  in  fact  in  the  whok^  field  of 
machine  tools,  is  the  universal  milling  machine,  one 
of  which  is  shown  in  Figure  110.  There  is  scarcely 
a  type  of  cut  known  in  the  machine  shop  which  can- 
not be  made  on  this  machine.  It  was  first  developed 
by  Brown  &  Sharpc  in  ISlil,  for  milling  the  flutes 
of  a  twist  drill.  The  machine  has  the  colunm,  knee, 
and  saddle  of  the  type  shown  in  Figure  104.  The 
table,  a,  however,  is  arranged  to  swivel  horizontally 
through  a  very  considerable  angle,  and  is  provided 
with  an  accurately  graduated  measuring  circle,  b. 

On  the  table  is  a  so-called  universal  head,  H,  shown 
in  Figures  110,  111,  and  112.    This  head  corresponds 
in  some  ways  to  the  head-stock  of  the  lathe,  although 
it    is    wholly    different    in    design.      The    adjustable 
bracket,  c,  wdiich  supports  the  outboard  end  of  the 
work,  corresponds  in  function  to  the  lathe  tail-stock, 
and  the  table  of  the  machine  to  the  lathe  bed.     In  a 
lathe  the  work  revolves  under  the  tool,  and  the  tool  is 
fed  past  the  w^ork.     In  this  case  the  milling  cutter 
revolves,  and  the  work,  carried  on  the  two  centers,  d 
and  e,  may  be  set  at  an  angle  with  reference  to  the 
cutter  and  fed  past  it  or  rotated— or  these  two  mo- 
tions may  be  used  simultaneously. 


1 

I 

'  'v- 

N 

b 

FIG.    110.      UNIVERSAL   MILLING   MACHINE 

325 


( I 


MILLING  MACHINES 


327 


FIGS.  Ill  AND  112.      INDEXING  HEADS 

The  lower  view  shows  a  head  arranged  for  six  spindles. 

Sharpe  Mfg.  Co. 

326 


Brown  & 


Milling  Teeth  of  Spur  Gear.— If  the  centers  are  set 
at  right  angles  to  the  axis  of  the  spindle,  and  the 
table  is  fed  sidewise,  the  cutter  will  mill  a  straight 
slot  parallel  to  the  axis  of  the  piece.  The  table  may 
then  be  returned,  the  work  may  be  indexed  through 
a  desired  angle  by  means  of  the  mechanism  in  the 
head,  and  the  cut  may  be  repeated.  Such,  for  in- 
stance, would  be  the  '* set-up"  for  milling  the  teeth  of 
a  small  spur  gear.  Or  the  table  may  be  clamped  in 
a  definite  position  under  the  cutter,  and  the  work 
given  a  continuous  rotary  feed  on  its  centers  without 
lateral  change  of  position.  By  this  method  a  circular 
slot  would  be  milled  around  the  work. 

Milling  Long  Spirals.— For  milling  long  spirals- 
such  as  the  flutes  of  a  twist  drill,  for  which  the  ma- 
chine was  originally  designed — the  table  is  turned 
horizontally  to  the  pitch  angle  of  the  groove,  and  the 
swiveling  joint  clamped  in  that  position.  The  drill, 
carried  between  the  centers,  d  and  e,  is  fed  longi- 
tudinally with  the  table  at  the  angle  so  set,  and  at 
the  same  time  given  a  rotary  power  feed  by  means  of 
the  head,  H.  The  combination  of  these  two  move- 
ments generates  the  helical  cut  required.  The  work 
may  then  be  run  back  to  its  starting  position,  the 
spindle,  d,  and  the  drill  being  cut  may  be  indexed  180 
degrees,  the  feeds  thrown  in  again  and  the  second 

groove  cut. 

Control  of  Rotary  Motion.— The  rotary  motion  of 
the  spindle  in  the  dividing  head  is  under  the  influ- 
ence of  two  controls,  one  of  which  performs  the  func- 
tion of  indexing  between  the  several  cuts,  the  other 
of  imparting  uniform  rotation  during  the  cut.     The 


i 


MILLING  MACHINES 


327 


FIGS.   Ill   AND  112.      INDEXING   HEADS 
The  lower  view  shows  .1  IiphM  nrnuiL'ed  for  six  spindles. 

Shjirpe   Mfjr.   <'o. 


Brown  A 


Milling:  Teeth  of  Spur  Gear.— If  the  centers  are  set 
at  right  angles  to  the  axis  of  the  spindle,  and  the 
table  is  fed  sidewise,  the  cutter  will  mill  a  straight 
slot  parallel  to  the  axis  of  the  piece.  The  table  may 
then  be  returned,  the  work  may  be  indexed  through 
a  desired  angle  by  means  of  the  mechanism  in  the 
head,  and  the  cut  may  be  repeated.  Such,  for  in- 
stance, would  be  the  *\set-up"  for  milling  the  teeth  of 
a  small  spur  gear.  Or  the  table  may  be  clamped  in 
a  definite  position  under  the  cutter,  and  the  work 
given  a  continuous  rotary  feed  on  its  centers  without 
hiteral  ehange  of  position.  By  this  method  a  circuhir 
slot  wouhl  l)e  miUed  around  the  work. 

Milling  Long  Spirals.— For  milling  long  spirals- 
such  as  the  (lutes  of  a  twist  drill,  for  which  the  ma- 
chine was  originally  designed — the  table  is  turned 
horizontally  to  the  pitch  angle  of  the  groove,  and  the 
swiveling  joint  clam])ed  in  that  position.  The  drill, 
carried  between  the  centers,  d  and  e,  is  fed  longi- 
tudinally with  the  table  at  the  angle  so  set,  and  at 
the  same  time  given  a  rotary  power  feed  by  nutans  of 
the  head,  11.  The  combination  of  these  two  move- 
ments generates  the  helical  cut  required.  The  work 
mav  then  be  run  back  to  its  starting  position,  th(> 
spindle,  d,  and  the  drill  being  cut  may  be  indexed  ISO 
degrees,   the  feeds  thrown   in  again   and   the  second 

groove  cut. 

Control  of  Rotary  Motion.— The  rotary  motion  of 
the  spindle  in  the  dividing  head  is  under  the  influ- 
ence of  two  controls,  oik*  of  whieh  performs  the  func- 
tion of  indexing  between  the  several  cuts,  the  other 
of  imparting  uniform   lot.Mtion   during  the  cut.     The 


328 


THE  MECHANICAL  EQUIPMENT 


MILLING  MACHINES 


329 


III 


spindle  that  holds  the  center,  d,  carries,  inside  of  the 
head,  a  worm  wheel  and  is  operated  by  a  hardened 
steel  worm  located  on  the  shaft,  f,  to  which  the  in- 
dex crank  and  handle,  g,  are  fastened.     When  the 
worm  IS  turned  by  means  of  the  index  crank,  the  in- 
dexing IS  accomplished.     The  index  plate  outside  is 
drilled  with  six  rows  of  small  holes.     The  crank  is 
turned  a  certain  number  of  holes,  and  a  spring  pin  in 
the  handle  engages  the  hole  that  gives  the  angle  de- 
sired    Two  adjustable  arms,  h,  h',  may  be  set  to  take 
just  the  number  of  holes  required  and  minimize  the 
chance  of  making  a  mistake  by  turning  the  handle  of 
the  indexing  crank  to  the  wrong  hole.    This  operation 
IS  performed  before  the  cut  is  begun,  to  turn  the  work 
through  the  angle  necessary  to  locate  the  cut. 

Continuous  Rotary  Feeding.-For  the  continuous 
rotary  feeding  during  the  cut,  the  index  plate  and 
the  worm  are  driven  together  from  the  table  feed- 
screw  through  the  train  of  change  gearing  shown  at 
the  end  of  the  table.     This  may  be  done  while  the 
index  pin  is  in  any  hole  of  the  plate.    Through  the 
interposition  of  change  gears  shown,  the  rate  of  ro- 
tary  feed  m  relation  to  longitudinal  traverse  may  be 
varied  to  control  the  angle  of  the  spiral  generated. 
For  rapid  indexing,  in  cutting  taps,  reamers,  and  so 
on,   the   worm  inside  may  be   disengaged   and   the 
spindle  may  be  turned  by  hand.    The  principal  divi- 
sions most  commonly  used  are  determined  directly  by 
the  single  row  of  holes  in  the  index  plate,  i,  which 
are  engaged  by  a  pin  operated  by  the  handle,  k. 

It  IS  possible  to  tip  the  head  in  a  vertical  plane 
so  that  the  spmdle,  d,  can  be  set  at  any  desired 


angle  from  10  degrees  below  the  horizontal  to  5 
degrees  beyond  the  perpendicular,  without  affecting 
the  operation  of  the  mechanism.  This  tipping  of  the 
head  renders  it  possible  to  make  cuts  on  conical  sur- 
faces. With  special  fixtures,  the  dividing  head  may 
be  used  to  index  more  than  one  piece  of  work  at  one 
time.  Figure  112  shows  a  head  coupled  to  a  special 
fixture  so  as  to  index  six  pieces  at  once  for  milling 
the  spiral  slots  in  push  screw-drivers. 

Various  forms  of  heads  are  made  for  different  pur- 
poses. Some  for  spiral  milling  are  without  the  verti- 
cal swiveling,  and  the  center  of  the  spindle,  d,  remains 
at  all  times  horizontal;  in  others,  the  indexing  heads 
are  made  without  either  automatic  driving  mechan- 
ism or  vertical  swiveling  and  are  used  for  straight 
work,  such  as  the  cutting  of  spur  gears.  The  hori- 
zontal swiveling  of  the  main  table  may  be  omitted, 
and  the  tool  driving  head  may  be  swiveled  instead. 
With  such  a  head,  the  work  which  otherwise  would 
require  a  universal  machine  can  be  done  on  one  of 
the  plain  column-and-knee  types,  as  shown  in  Figure 
111,  where  the  work  is  at  right  angles  to  the  main 
axis  of  the  machine,  and  the  cutter  axis,  instead  of 
the  table,  is  set  at  the  pitch  angle. 

The  universal  miller  is  distinctly  a  tool-room  ma- 
chine. The  adaptability  which  enables  it  to  perform 
almost  every  type  of  machining  operation  necessarily 
involves  refinements  of  design  and  delicate  adjust- 
ments that  require  skilful  handling. 

Planer  Type  of  Milling  Machine.— Nearly  all  the 
machines  described  are  for  small  or  moderate-sized 
work.    The  milling  principle,  however,  has  been  ap- 


*    ft.. 


330 


THE  MECHANICAL  EQUIPMENT 


plied  also  to  large  work  and  heavy  production.  Figure 
113  shows  a  machine  of  the  so-called  planer  type.    The 
reason  for  the  name  is  obvious,  as  the  general  appear- 
ance of  the  machine  is  closely  similar  to  that  of  the 
planer.    There  are  the  main  bed,  the  traversing  table, 
the  uprights,  the  cross  rail,  and  the  tool  heads  of  the 
standard  planer.    Its  action  however  is  materially  dif- 
ferent.    The  tool  heads  of  a  planer  contain  single- 
edged  cutting  tools  which  have  no  motion  other  than 
the  feed.    The  cutting  heads  of  this  machine  carry  re- 
volvmg  spindles  and  milling  cutters  usually,  but  not 
always,  of  the  face-milling  type. 

In  the  planer  the  table  and  the  work  move  back 
and  forth  under  the  cross  rail  many  times  while  a 
cut  is  being  made.    In  this  machine  the  action  is  like 
that   of  a  Lincoln   miller.   Figure   101.     The   work 
moves  forward  slowly  at  the  speed  of  the  feed,  and 
passes  under  the  cutting  tool  but  once.    The  cutting 
action  in  this  case  is  continuous,  instead  of  intermit- 
tent as  in  the  case  of  the  planer.     Machines  of  this 
type  are  made  in  sizes  from  20  inches  square  by  8 
feet  traverse,  to  10  feet  square  by  30  feet  traverse. 
For  special  manufacturing  operations,  they  are  often 
made  with  heavy  fixed  cross  rails  cast  solid  with  the 
uprights. 

In  the  machine  shown,  the  cross  rail,  a,  is  adjust- 
able, and  one  of  the  vertical  spindles,  b,  is  equipped 
with  a  vertical  or  boring  feed.  The  other  head,  c, 
is  a  straight  milling  head.  The  cross  rail  may  carry 
one  milling  head,  or  two,  according  to  the  size  of  the 
machine,  and  frequently  milling  heads,  as  at  d,  are 
provided  on  one  or  both  of  the  uprights.     These  ma- 


FIGS.    113    AND   114.      PLANERS 
The  upper,  Fig.  113,  is  a  milling  macliine  of  the  planer  type,  built  by 
the  Ingersoll  Milling  Machine  Co.    The  lower,  Fig.  114,  is  a  rotary 
planer  made  by  Niles-Bement-Pond  Co.  o6i 


•?1  1 


1^1 


;  i  \ 


1! 


' 


^11 


THK  MECHAMCAL   K(^l'IPME\T 


p  led  also  lo  large  work  and  Ikvivv  produclio.i.   Fiou,v 
113  shows  a  machino  of  the  so-ealled  planer  tyi)(>.    The 
reason  for  the  name  is  obvious,  as  the  general  appear- 
ance of  the  machine  is  closely  similar  to  that  of  th(' 
planer.    There  are  the  main  hod,  the  traversing  table, 
the  uprights,  the  cross  rail,  and  the  tool  heads  of  the 
standard  planer.    Jts  action  however  is  materiallv  dif- 
ierent.     The  tool   heads  of  a   planer  contain   si'n<>l(>- 
edged  cutting  tools  which  have  no  motion  other  than 
the  feed.    The  cutting  heads  of  this  machine  carrv  re- 
volving spindles  and  milling  cutters  usuallv,  but  not 
always,  of  the  face-milling  type. 

In  the  planer  the  table  and  the  work  move  back 
and  forth  under  tlie  cross  i-ail  manv  tinu^s  while  a 
cut  IS  being  made.    In  this  macliine  the  action  is  like 
that    of   a    Lincoln    miller,    Figure    101.      The    work 
moves  forward  slowly  at  the  speed  of  the  feed    and 
passes  under  tlie  cutting  tool  but  once.     The  cu'tting 
action  in  this  case  is  continuous,  instead  of  iidermit'^ 
tent  as  in  the  case  of  the  planer.     .Alachines  of  this 
type  are  made  in  sizes  from  20  inches  squai-e  by  S 
feet  traverse,  to  10  feet  square  by  30  feet  traverse. 
For  special  manufacturing  operations,  thev  are  often 
made  with  heavy  fixed  cross  rails  cast  solid  with  the 
uprights. 

In  the  machine  shown,  the  cross  rail,  a,  is  adjust- 
a])le,  and  one  of  the  vertical  spindles,  b,  is  equipped 
with  a  vertical  or  boring  feed.  The  other  liead,  c, 
IS  a  straight  milling  head.  The  cross  rail  may  carrv 
one  milling  head,  or  two,  according  to  the  size  of  tli'c 
machines  and  frecjuently  milling  heads,  as  at  d,  an- 
p.-'»vided  on  ()n<'  or  both  of  the  uprights.     These  m;i 


FIGS.    113    AND    114.      PLANERS 
The  upper   Fi^'.  113,  is  a  millinj:  machine  of  the  planer  type,  built  by 
the  Inpersoll  Millinj;  Machine  Co.     The  lower,  Fig.  114,  is  a  rotary 
phuier  made  by  Niles-Bemeut-Pond  Co.  '^i- 


332 


THE  MECHANICAL  EQUIPMENT 


chines  can  do  nearly  all  the  work  that  could  be  done 
by  a  planer  of  corresponding  size,  and  will  do  it 
much  more  rapidly,  finishing  it  from  the  rough  piece 
in  a  single  pass.  They  are,  however,  distinctly  a 
manufacturing  type  of  machine,  and  are  not  so  well 
adapted  for  special  jobbing  work  as  the  planer. 

A    machine   of   the   proportions    shown    is    by   no 
means  confined  to  operation  on  long  narrow  work. 
Special    fixtures    are    often    provided    to    mount    a 
series  of  castings— as  automobile  cylinders,  for  in- 
tance— in  a  long  row  one  behind  another.    When  the 
fixtures  have  been  filled,  the  table  is  started  past  the 
cutters  on  the  forward  feed.     As  each  piece  passes 
the  cutting  heads,  it  is  finished.    Owing  to  the  slow 
feed  of  the  table,  the  pieces  that  have  been  passed 
under  the  rail  may  be  removed  while  the  cut  is  in 
progress  and  new  work  may  be  substituted.     When 
the  last  piece  in  the  row  is  finished,  the  quick  re- 
verse traverse  may  be  thrown  in,  the  table  returned, 
and  a  new  cut  started  on  the  fresh  pieces  that  have 
been  put  in  at  the  front  end  of  the  table.     While 
these  are  being  cut,  the  last  pieces  may  be  replaced, 
at  the  other  end  of  the  machine,  so  that,  although  the 
feed  is  reciprocating,  the  cutting  action  may  be  al- 
most as  continuous,  as  in  the  rotary  feed  shown  in 
Figure  106. 

Rotary  Planer.— Another  machine,  known  as  the 
rotary  planer,  shown  in  Figure  114,  is  in  reality  a 
face-milling  machine  for  machining  large  flat  faces. 
The  work  is  clamped  to  the  fixed  table  in  the  front 
of  the  machine,  and  a  large  revolving  head,  mounted 
on  the   travelling  carriage,   passes   along  the   table. 


MILLING  MACHINES 


333 


The  head  carries  a  series  of  single-edged  tools  of  the 
planer  type,  which  are  inserted  in  the  holes,  a,a,  in 
the  face,  and  are  secured  by  means  of  screws  oper- 
ated from  corresponding  holes,  b,b,  in  the  rim. 

The  carriage,  with  its  revolving  head,  is  slowly  fed 
horizontally  along  the  ways — the  cut  begins  at  one 
side  of  the  piece  and  passes  progressively  across  the 
face.  It  will  be  noted  that  the  cutting  tools  drop 
slightly  below  the  level  of  the  bed  on  which  the 
work  is  clamped,  to  insure  that  the  bottom  is  finished, 
and  the  width  of  the  face  of  the  work  must  not  be 
greater  than  the  diameter  of  the  circle  of  the  cutting 
tools.  Machines  of  this  type  will  finish  flat  faces  on 
large  castings  with  astonishing  rapidity. 


Ill 


CHAPTER  XIX 
GEAK-CUTTING 

Two  Systems  of  Tooth  Forms.— The  cutting  of  gear 
teeth  is  one  of  the  important  operations  in  the  ma- 
chine shop,  and  a  wide  variety  of  machines  have  been 
developed  for  this  purpose.  The  kinds  of  gears  are 
so  varied  and  the  mechanical  motions  required  to  cut 
some  of  them  are  so  intricate,  that  in  the  design  of 
no  other  type  of  machine  tool  have  more  skill  and 
ingenuity  been  displayed.  Before  treating  of  the  ma- 
chinery, it  is  necessary  to  consider  some  points  in  re- 
gard to  tooth  forms  and  types  of  gears. 

Two  systems  of  tooth  forms  have  had  wide  use; 
they  are  known,  from  the  curves  that  govern  their 
shapes,  as  the  cycloidal  and  the  involute.    Teeth  with 
sides  formed  of  these  curves  will  transmit  motion 
from  one  gear  to  another,  quietly  and  smoothly,  at  a 
constant  velocity  ratio.     In  both  systems,  the  teeth 
are  designed  with   reference  to   a  circle   called  the 
pitch    circle    (see   Figure    115),    and    the    action    of 
the  teeth  is  designed  to  duplicate  exactly  the  mo- 
tion that  would  be  derived  from  the  rolling  of  two 
pitch  circles  together.     While  tooth  forms  are  laid 
out  as  lines  related  to  a  pitch  circle,  the  gear  always 
has  a  finite  thickness,  and  the  sides  of  the  teeth  are 
actually  surfaces  related  to  a  pitch  cylinder,  or  cone, 

334 


GEAR  CUTTING 


335 


80S9  fine  of  Rack    • 

I    *|  V-Pitch  line  of  Rack 

Pitch  C'irch 


Pitch  Circle-. 
Base  Circle 


Base  Circle 


Imaginaiy   -- 
spring  being 
/  unnraffed 


.,    Describing  Point 

\\c        Circular  Pitch 
I !  'o 

FIG.  115.  PAIR  OF  SPUR  GEARS-  SHOWING  TOOTH 
SURFACES  FORMED  FROM  INVOLUTE  CURVES 


y////y/////////////////////////. 


FIG.  118.  THE  DESCRIBING-GENERATING 
PRINCIPLE  OF  FORMING  GEAR  TEETH 


Pitch  Circle 


<5b*0 


i^^ 


FIG.  1 19.  THE  FORM-GENERATING  PRINQPLE 
OF  FORMING  GEAR  TEETH 


FIO.  116.  CUTTING  A  BEVEL  GEAR  BLANK  WITH 
A  FORMED  MILUNG  CUTTER 


A 
Gear-- 
being 
filmed 


Forminqy 
Rack 


FIG.  117.   THE  TEMPLATE  PRINCIPLE  OF 
FORMING  GEAR  TEETH 


FIG.  120.  FOUR  WAYS  OF  USING  THE  FORM- 
GENERATING  PRINCIPLE 


FIGS.    115-120.      CUTTING  GEAR  TEETH 


ill 

t 


k    \ 


336 


THE  MECHANICAL  EQUIPMENT 


GEAR-CUTTING 


337 


of  which  the  pitch  circle  is  a  cross  section.  The 
theory  of  these  systems  is  somewhat  intricate,  and 
need  not  be  given  here.*  The  cycloidal  system  is  the 
older;  it  was  developed  about  1830,  but  it  is  now 
falling  into  disuse,  because  teeth  formed  on  the  in- 
volute system  are  simpler  to  generate  and  stronger. 
Although  formed  milling  cutters  may  be  obtained  for 
both  kinds  of  teeth,  practically  all  machine-cut  gear- 
ing is  now  based  on  the  involute  system;  only  that 
system,  therefore,  will  be  considered. 

Spur  Gears.— The  gears  in  general  use  belong  to 
one  of  the  following  four  types:  spur  gears,  helical 
gears,   bevel   gears,    and   worm   gears.     Spur   gears 
transmit  motion  between  parallel   shafts,   and   their 
action  in  every  way  duplicates  that  of  two  pitch  cyl- 
inders when  rolling  upon  each  other  (see  Figure  115). 
Spur  gears  may  have  as  few  as  twelve  teeth.    Theoret- 
ically, they  may  have  still  fewer,  but  practically  this 
is  the  limit,  since  the  tooth  form  grows  weak  and 
other  troubles  are  encountered  when  fewer  teeth  are 
used.    Small  spur  gears  are  called  pinions  when  they 
mesh  with  a  larger  gear,  which  is  ordinarily  termed 
the  spur.    As  the  size  of  the  wheel  grows  larger,  the 
sides  of  the  teeth,  a,  become  flatter  until  the  limit  is 
reached  in  a  rack  or  straight  bar,  in  which  the  sides 
have  become   a  plane   surface,   at  b.     Usually   two 
gears    run    on    the    outside    of    each    other,    as    in 
Figure    115,    or   a   and    b.    Figure    126.      Occasion- 

*  Those  who  wish  to  follow  up  this  subject  are  referred  to  some 
standard  book  on  mechanism,  such  as  "Elements  of  Mechanism." 
Schwamb  and  Merrill;  "Mechanism."  Keown ;  "Treatise  on  Gear 
Wheels,"  Geo.  D.  Crrant,  or  some  of  the  standard  works  on  machine 
design. 


ally,  however,  a  small  pinion  will  engage  with  the  in- 
ner surface  of  the  rim  of  a  large  gear,  as  c  and 
d  in  Figure  126,  in  which  case  the  large  one  is 
called  an  internal  gear.  Figure  126  also  shows  a 
rack  engaging  a  pinion,  f.  In  spur  gearing  the 
teeth  are  straight,  parallel  to  the  axis  of  the  gear  and 
to  each  other,  and  of  uniform  size  and  shape  through- 
out the  whole  length. 

Helical  Gears. — These  gears  are  similar  to  spurs,  as 
regards  both  use  and  general  design,  except  that  the 
teeth,  instead  of  being  straight,  are  wrapped  around 
the  pitch  surface,  each  as  a  uniform  helix.  Although 
not  parallel  to  the  axis,  they  are  parallel  to  each 
other  and  of  uniform  size  and  shape,  as  in  spur  gear- 
ing. Helical  gears  are  smoother  in  action  than  the 
ordinary  gear,  and,  as  a  result  of  the  improved 
methods  of  manufacturing  them,  they  are  coming 
into  increasing  use. 

Bevel  Gears. — These  gears  are  used  for  transmitting 
motion  between  axes  which  are  in  the  same  plane  but 
not  parallel.  The  teeth,  theoretically,  are  formed  on 
pitch  surfaces  that  are  rolling  cones,  instead  of  roll- 
ing cylinders  as  in  spur  gears,  the  apexes  of  the  cones 
coinciding  with  the  intersection  of  the  two  axes  of 
the  gears.  The  cross-section  of  a  spur-tooth  gear  is 
the  same  in  any  plane  at  right  angles  to  the  axis. 
The  cross-section  of  a  bevel  gear  grows  smaller  and 
smaller  as  it  approaches  the  apex  of  the  pitch  cone, 
since  all  the  elements  of  each  tooth  center  in  toward 
it  (see  Figure  117). 

Worm  Gears. — A  worm  gear  is  a  toothed  wheel 
operated  by  a  screw  that  meshes  with  it;  the  screw 


iri! 


338 


THE  MECHANICAL  EQUIPMENT 


GEAR-CUTTING 


339 


t^ 


lies  tangential  to  the  face,  with  its  axis  at  right 
angles  to  the  axis  of  the  wheel.  A  worm  and  worm 
wheel  are  shown  at  g  and  h  in  Figure  126— in  cross- 
section  in  the  main  view,  and  in  plan  in  small  view 
above.  In  the  upper  view  the  teeth  on  the  worm 
wheel,  though  not  shown  so,  in  reality  extend  entirely 
around  it.  This  type  of  gear  is  very  useful  for  rapid 
reductions  of  speed,  and  for  fine  dividing  and  index- 
ing when  it  is  necessary  to  control  the  angular  mo- 
tion with  great  accuracy. 

There  are  various  other  forms  of  gear  wheels,  such 
as  skew  gears  and  hyperbolic  gears,  but  since  they 
are  not  extensively  used  they  need  not  be  considered 
here. 

Formed-Tooth  Principle.— A  gear-cutting  machine 
operates  on  one  of  the  four  following  principles:  the 
formed-tooth  principle,  the  template  principle,  the 
describing-generating  principle,  and  the  form-gener- 
ating principle. 

Of  these  the  oldest,  simplest,  and  most  widely  used 
is  the  formed-tooth  principle.  A  *' blank,''  which 
consists  of  the  gear  wheel  bored,  faced,  turned,  and 
ready  to  be  cut,  is  mounted  on  a  suitable  arbor,  and 
the  space  between  two  teeth  is  removed  by  a  cutting 
tool  that  has  been  accurately  formed  to  the  shape  of 
the  open  space  between  the  teeth.  The  work  may  be 
done  on  a  shaper,  in  which  case  the  cutting  tool  is 
reciprocated  across  the  face  of  the  blank,  parallel  to 
its  axis,  and  is  fed  in  gradually  toward  the  center 
until  the  required  depth  has  been  reached.  The  tool 
is  then  raised  to  its  original  position,  the  gear  blank 
is  indexed,  and  the  action  is  repeated  until  all  the 


spaces  have  been  cut  out,  leaving  teeth  of  the  re- 
quired form  between  them.  It  is  far  more  common, 
however,  to  embody  this  principle  in  a  milling  oper- 
ation (see  Figures  121  and  123).  In  this  case,  a 
formed  milling  cutter  of  the  required  shape,  like  that 
shown  in  Figure  122,  is  used.  The  gear  blank  is 
mounted  on  an  arbor,  as  already  described,  and  the 
cutter  is  fed  once  across  the  face,  parallel  to  the  axis, 
leaving  a  finished  surface  behind  it.  The  cutter  is 
then  returned  to  its  original  position,  the  blank  is  in- 
dexed, and  the  cut  is  repeated  until  the  gear  is  done. 
The  milling  cuttor,  shown  in  Figures  116  and  122,  is 
of  the  relieved  type;  that  is,  the  sides  of  the  cutting 
teeth  retain  the  correct  form  as  they  fall  away  from 
the  cutting  edge.  A  cutter  so  relieved  may  be  ground 
on  the  face  and  will  still  cut  the  correct  shape.  The 
deviation  from  correct  work  depends  partly  upon  the 
accuracy  of  the  ** set-up,"  and  partly  upon  the  ac- 
curacy with  which  the  milling  cutter  is  made.  Theo- 
retically, there  should  be  a  cutter  of  a  different  shape 
for  each  number  of  teeth  required  for  every  pitch,  or 
size.  Practically,  however,  the  true  form  of  the  tooth 
changes  so  little  that  for  ordinary  work  eight  cutters 
for  each  pitch  may  be  used  for  everything  from  a 
twelve-toothed  pinion  to  a  rack.  The  commercial 
cutters  on  the  market  are  the  following: 

No.  1  will  cut  wheels  from  135  teeth  to  a  rack 


■»  %^» 

2 

55 

134 

teeth 

3 

35 

54 

4 

26 

34 

5 

21 

25 

6 

17 

20 

7 

14 

16 

8 

12 

13 

r^is 


n  ■' 


!    . 


340 


THE  MECHANICAL  EQUIPMENT 


GEAR-CUTTING 


341 


i  'Iv 


For  work  requiring  more  accurate  teeth,  half  num- 
bers may  be  obtained: 

No.  V/z  will  cut  wheels  from  80  teeth  to  134  teeth 


''  2y2 

'      42     '' 

<  ( 

54 

''  sy2 

'      30     *' 

(< 

34 

"  ^y2 

'      23     '' 

<  < 

25 

*'  hy2 

'      19     *' 

(< 

20 

"  65^ 

*      15  and 

16 

"  7M 

'     13  teeth 

• 

If  the  holes  in  the  blanks  are  straight  and  the 
hubs  do  not  project  beyond  the  face,  a  number  of 
blanks  may  be  fastened  together  on  the  arbor  and 
cut  at  the  same  time  (see  Figure  125).     Care  must 
be  taken  to  make  sure  that  the  sides  of  the  blanks  are 
truly  parallel;  otherwise,  when  the  blanks  are  clamped 
together,  they  will  spring  the  arbor  and  cause  it  to 
run  out  making  it  impossible  to  produce  accurate 
teeth.     Machines   using   formed   milling  cutters   are 
often  automatic,  and  several  may  be  operated  by  one 
attendant.    When  stock  gears  are  made  in  large  quan- 
tities, the  machines  may  be  simplified  if  a  separate 
one  is  used  for  each  size  and  kind  of  gear,  for  such 
an  arrangement  permits  of  using  a  plain  index  wheel 
that  has  the  same  number  of  holes  as  there  are  teeth 
to  be  cut.    With  this  arrangement,  teeth  may  be  cut 
at  random  around  the  wheel  to  avoid  uneven  heating. 
The  cutting  of  spur  gears  by  means  of  formed  milling 
cutters    is    the    cheapest    method,    and    is    accurate 
enough  for  all  ordinary  work. 

Formed  milling  cutters  are  also  widely  used  for 
cutting  bevel  gears,  but  are  not  so  satisfactory  with 
bevels  as  with  spur  gears.  Since  bevel-gear  teeth 
taper  down  toward  the  apex  of  the  pitch  cone,  the 


sides  of  the  cut  between  them  can  never  be  parallel 
(see  Figure  116),  and  it  is  therefore  impossible,  with 
a  formed  cutter  that  has  fixed  curves,  to  give  the  cor- 
rect shape  to  the  tooth  throughout  its  entire  length. 
The  practice  is  to  use  a  cutter  that  is  correct  for  the 
large  end  of  the  tooth,  and  to  set  the  work  so  that 
the  tooth  is  cut  to  the  proper  thickness  on  the  pitch 
line  at  the  small  end.  The  tops  of  the  teeth  are  then 
too  thick  at  the  small  end,  and  they  are  filed  off.  The 
milling  process  is  more  satisfactory  with  narrow- 
faced  bevel  gears  than  with  wide  ones,  as  the  devi- 
ation from  the  correct  form  is  not  so  marked.  Since 
the  teeth  approach  one  another,  the  cut  between  them 
must  narrow  down,  and  it  is  evident  that  but  one  side 
of  the  tooth  space  can  be  cut  at  a  time;  accordingly 
at  least  two  cuts  must  be  taken  for  each  space,  the 
two  cuts  matching  up  on  the  bottom.  Figure  116 
shows  a  milling  cutter  cutting  the  left-hand  side  of 
a  bevel-gear  tooth;  the  opposite  cut  on  the  other  side 
of  the  groove  has  been  made. 

Template  Principle.— The  second,  or  template  prin- 
ciple, is  illustrated  in  Figure  117,  which  shows  a 
small  portion  of  a  bevel  gear  with  the  teeth  already 
cut.  The  letter  o  marks  the  apex  of  the  pitch 
cone,  toward  which  all  the  tooth  elements,  such  as  a— b 
and  c— d  center.  A  template.  A,  having  a  curved  por- 
tion, e — f,  of  the  correct  form  required  for  a  tooth  at 
the  distance  a'— o  from  the  apex.  If  the  line  a'— o  be 
held  at  o,  and  the  other  end  be  moved  along  the  tem- 
plate to  c',  it  would  follow  the  side  of  the  required 
tooth,  a— b— c— d.  The  principle  is  applied  practi- 
cally by  having  a  shaper  tool  mounted  in  a  frame, 


'ill 

*  .1  i  ♦ 


* 


342  THE  MECHANICAL  EQUIPMENT 

which  swings  about  the  point  o  under  the  influence 
ot  the  former,  A,  the  point  of  the  cutting  tool  moving 
backward  and  forward  from  a  to  b  across  the  face 
of  the  gear  on  the  line  a'-o.     A  roller,  B,  on  a 
swinging  frame,  follows  the  former  from  a'  to  c'  and 
guides  the  tool  in  a  series  of  cuts  that  will  produce 
the  surface  required.    According  to  this  method,  the 
bevel-gear  blank  is  first  gashed  with  grooves  which 
rough  out  most  of  the  stock,  leaving  the  sides  to  be 
limshed.  The  corresponding  sides,  x-x,  of  each  tooth 
are  finished,  and  a  new  former,  curved  in  the  oppo- 
site direction,  is  used  to  form  the  opposite  sides  y—y 
in  a  second  series  of  cuts.     This   method  is'  used 
mainly  m  connection  with  bevel  gears,  as  shown,  but 
may  be  used  for  cutting  spur  gears;  the  only  differ- 
ence,  m  the  latter  case,  is  that  the  successive  strokes 
of  the  cutting  tool,  instead  of  centering  on  the  point 
o,  are  parallel.    In  fact,  a  spur  gear  is  a  special  case 
of  a  bevel  gear,  in  which  the  point  o  has  moved  off 
toward  infinity,  and  the  pitch   cone  has  become  a 
cylinder.     The  cutting  tool  is  made  narrow  enough 
to  go  through  the  opening  between  the  teeth  at  the 
smallest  point,  and  right-  and  left-hand  cuts  match  up 
on  the  bottom,  as  in  the  milling  operation  illustrated 
m  Figure  116. 

The  template  method  applied  to  bevel  gearing  is 
much  more  accurate  than  the  formed-cutter  method. 
The  only  errors  possible  are  inaccuracies  in  the  shape 
and  setting  of  the  former,  and  the  inability  of  the 
tool  to  coincide  exactly  with  the  radial  line  to  the 
apex.  These  inaccuracies  are  small,  however,  and 
teeth  cut  on  this  principle  are  very  .satisfactory. ' 


GEAR-CUTTING 


343 


Describing-Generating  Principle. — The  describing- 
generating  principle  duplicates  mechanically  the 
method  of  drawing  the  involute  curve.  This  curve, 
which  forms  the  basis  of  the  sides  of  involute  teeth, 
is  the  one  traced  by  a  point  in  a  string  which  is  un- 
wrapped from  a  cylinder  (see  Figure  115).  The  circle 
corresponding  to  the  cylinder  is  called  the  base  circle. 
Suppose  that  the  point  of  a  shaper  tool,  a,  is  held 
against  the  side  of  a  gear  blank  mounted  on  center, 
b,  below  it,  and  that  it  touches  the  gear  at  the  top 
of  the  base  circle.  If  the  base  circle  of  the  gear  blank 
is  rolled  to  the  right  along  a  horizontal  line,  c — d, 
through  the  point  of  the  tool,  the  tool  will  trace  an 
involute  curve,  a — e,  on  the  side  of  the  gear.  If,  dur- 
ing this  process,  the  shaper  tool  is  given  a  recipro- 
cating motion  across  the  face  of  the  gear,  it  will  cut 
a  true  involute  surface  that  may  be  used  as  one  side 
of  the  tooth.  In  practice,  the  side  of  the  tooth  would 
be  cut  in  the  reverse  direction,  from  e  to  a,  but  the 
principle  is  the  same.  By  indexing  the  blank  all 
around,  the  corresponding  sides  of  each  tooth  may  be 
similarly  generated.  By  setting  the  blank  over  the 
thickness  of  a  tooth  and  making  the  sidewise  motion 
to  the  left  instead  of  to  the  right,  the  opposite  sides 
of  the  teeth  may  be  formed.  This  method  may  be  used 
for  cutting  either  spur  or  bevel  gears.  In  the  case 
of  spur  gears,  the  strokes  of  the  cutting  point,  a,  will 
all  be  parallel.  In  the  case  of  bevel  gears,  they  will 
center  down  to  a  common  point  corresponding  to  o 
in  Figure  117. 

Perm-Generating  Principle. — The  fourth  principle 
— ^the  form-generating — is  based  upon  the  fact  that 


344 


THE  MECHANICAL  EQUIPMENT 


GEAR-CUTTING 


345 


any  gear  in  an  interchangeable  set  will  run  with  any 
other  gear  of  the  set.     This  is  true  no  matter  what 
the  number  of  teeth  may  be,  and  applies  to  racks  as 
well  as  to  gears  of  any  diameter.     The  operation  of 
this  principle  may  be  reversed  and  utilized  to  make 
one  gear  form  cut  another.    If  one  of  the  gears  is  of 
hardened  tool  steel,  and  has  the  edges  along  one  side 
of  the  teeth  sharp  enough  to  act  as  cutting  edges, 
that  gear  may  reciprocate  sidewise  across  the  face 
of  the  other,  the  cutting  gear  and  the  blank  being 
rotated,  meantime,  as  if  they  were  in  mesh.     The 
result  of  this  action  is  that  the  teeth  of  the  cutting 
gear  forms  grooves  in  the  other  which  will  conform 
exactly  to  the  space  between  the  teeth  that  a  mating 
gear  should  have.    This  action  is  illustrated  in  Figure 
119.     The  successive  positions  shown  represent  the 
position  of  the  tooth,  a,  with  reference  to  the  work; 
the  shaded  portion,  b,  shows  the  material  that  would 
be  cut  out  by  one  of  the  transverse  passes  of  the  cut- 
ting  gear.    The  distance  between  the  successive  posi- 
tions in  the  figure  is,  of  course,  far  greater  than  it 
would  be  in  actual  practice.     This  principle  is  em- 
bodied in  a  Fellows  gear-shaper.  Figures  125  and  126, 
and  may  be  used  in  cutting  either  spur  or  spiral 
teeth.    In  the  former  case,  the  gears  have  no  rotation 
during  the  cutting  stroke;  in  the  latter  instance,  they 
are  given  a  uniform  rotation  during  the  cutting  ac- 
tion, which  results  in  a  spiral  tooth  instead  of  a 
straight  one.     This  form-generating  principle  gives 
very  accurate  work.     The  operation  known  as  bob- 
bing, which  will  be  described  later,  is  based  on  this 
principle. 


The  cutting  gear  may  have  any  convenient  number 
of  teeth,  or  may  be  part  of  a  rack.  The  teeth  of  a 
rack  are  often  used  to  do  the  forming,  as  the  side  of 
a  rack  tooth  is  a  straight  line,  and  therefore  easier 
to  originate.  Figure  120  shows  the  generating  prin- 
ciple applied  in  four  ways.  At  A  the  rack  is 
rolled  past  a  plastic  gear  and  the  teeth  are  moulded 
by  impression.  x\t  B  the  tool,  T,  to  the  right,  has 
a  straight  cutting  edge,  which  conforms  to  one  side 
of  a  tooth  in  an  imaginary  rack.  If  this  is  made  to 
travel  to  the  right,  as  the  rack  did  in  A,  and  if  at 
the  same  time  it  has  a  sidewise  reciprocating  mo- 
tion, it  will  cut  out  the  side  of  the  tooth  which  it 
touches.  If  the  cutting  tool  has  two  cutting  edges, 
corresponding  to  the  opposite  sides  of  a  tooth  on  the 
rack,  as  at  T',  it  will  cut  out  both  sides  of  the 
tooth  space.  Instead  of  a  reciprocating  cutter,  a 
milling  cutter  may  be  used,  as  at  C,  the  side  of  the 
cutter  conforming  to  the  imaginary  tooth  rack  and 
duplicating  in  every  way  the  action  of  the  shaper 
cutter,  T,  in  B.  In  D  the  side  of  an  emery  wheel 
is  substituted  for  the  milling  cutter  of  C;  the  action 
is  the  same  in  both  cases.  Of  these  four  means,  the 
first,  or  impression,  method  is  of  course  impractic- 
able; it  is  mentioned  only  to  help  to  illustrate  the 
principle.  The  shaping  and  milling  methods,  shown 
at  B  and  C,  are  widely  used.  The  grinding  method, 
shown  at  D,  is  used  to  true  up  the  surfaces  of  gears, 
which  have  been  cut  by  one  of  the  previous  methods, 
and  then  hardened;  it  is  the  most  accurate  of  all. 

Spur-Gear-Cutter. — Only  a  few  of  the  typical  gear- 
cutting  machines  can  be  shown,  as  there  are  literally 


w 


15 


346 


THE  MECHANICAL  EQUIPMENT 


scores  of  designs.     The  most  generally  used  is  the 
automatic  spur-gear-cutter,   similar  to   those  shown 
in  Figures  121  and  123.     In  the  machine  shown  in 
figure  121,  the  gear  blanks  are  mounted  on  a  hori- 
zontal arbor,  which  is  carried  in  the  spindle,  a,  and 
IS  provided  with  an  adjustable  outboard  support,  b, 
in  order  that  the  greatest  possible  firmness  may  be 
given  to  the  work.    This  arbor  is  capable  of  rotation, 
but  IS  under  the  control  of  a  large  and  very  accurately 
divided  index  wheel,  in  the  casing  c,  which  controls 
the  spacing  of  the  cut  around  the  rim.     A  formed 
milling  cutter,   like   that   shown  in   Figure   122,   is 
carried  on  a  spindle,  d,  and  is  given  a  feed  across  the 
tace  of  the  gear.    As  each  cut  is  completed  the  car- 
nage, e,  IS  returned,  the  work  is  indexed  to  the  next 
position,  and  the  next  cut  is  made.    All  the  motions 
ot  the  machine  are  automatic;  the  speed  of  indexing 
IS  independent  of  the  rate  of  feed  and  speed  of  the 
cutter,  and  the  indexing  is  done  as  rapidly  as  it  is 
possible  to  do  it  without  causing  shock.     The  feed 
mechanism  of  the  cutter  is  disengaged  during  the 
indexing,  and  becomes  operative  only  on  its  com- 
pletion.   FigTire  123  shows  the  position  of  the  cutter 
and  the  work  reversed;  the  gear  blanks  are  held  on 
the  vertical  arbor,  a,  carried  by  a  saddle,  b,  on  the 
i,       1  machine.     The  index  wheel  is  inside  the 
saddle.    The  cutter  spindle,  c,  is  carried  by  the  up- 
right,  and  has  a  vertical  travel  instead  of  a  horizontal 
one.    The  principles  of  action  are  not  altered  by  this 
change  m  arrangement. 

Machine  Embodying  Template  Principle-Figure 
124  shows  a  machine  embodying  the  template  prin- 


.:^i 


m 


346 


THE  AlHcilAXUAI.  IXjLlPMENT 


scores  of  (lo^^igns.     Tlio  n.osl   Kvn<.rallv  usod   is  the 
autoniatic    spur-gear-cuttor,   similar   to    those   sliown 
in  Hgurcs   121  and   123.     In   tlic  inaoliine  sliown  in 
l^igure  121,  the  gen,-  l.lanks  arc  inoimlwl  on  a  hori- 
zontal arhor,  whi,-],  is  earrio.l  i„  the  spin.llo,  a,  and 
IS  provided  with  an  a.l.justal.l..  oiitlmard  support    h 
in  order  that  the  greatest  possible  firmness  niav'  be 
given  to  the  work.     This  arl.or  is  eapahle  of  rotation, 
but  IS  under  the  control  of  a  large  and  verv  accurately 
divided  mde.x  wheel,  in  the  casing  c.  which  controls 
the  spacing  of  the  cut   aroun.l   the  rim.     A   formed 
milling   cutter,    like    that    shown    in    Fi<.ure    f-w    is 
carried  on  a  spindle,  d,  and  is  given  a  feed  aeross'the 
tace  of  the  gear.    As  each  cut  is  completed  the  car- 
nage, e,  IS  returned,  the  work  is  indexe.l  to  the  next 
position,  and  the  next  cut  is  nuul...     All  the  motion.s 
ot  the  machine  are  automatic;  the  speed  of  indexin- 
IS  indepen.lent  of  the  rate  of  feci  and  speed  of  the 
cutter    and  tlie  imle.xing  is  done  as  rapidiv  as  it  is 
possible  to  do  it  without  causing  shock.    'The  feed 
mechanism   of  the   cutter  is   <lisengage,l   during   the 
indexing,   and    l.ecoines    operative   onlv    on    its   com- 
pletion.   Figure  1-2?,  shows  the  position  of  the  cutter 
and  the  work  reversed;  the  gear  blanks  are  held  on 
the  vertical  arbor,  a,  carrie<l  by  a  saddle,  b,  on  the 
...,       Z  "i''f'l'i"<^-     The  index  wheel  is  inside  the 
saddle.     The  cutter  spindle,  c,  is  carried  bv  the  up- 
right,  and  has  a  vertical  travel  instead  of  a  horizontal 
one.    The  principles  of  action  are  not  altered  by  this 
change  in  arrangement. 

Machine  Embodying  Template  Principle.-Figure 
124  .shows  a  machine  embodying  the  template  prin- 


s 

i  < 

s  -•  ^ 
■^  p 

>:^    S3     H^ 

<    - 

OS  -' 

Oh    = 


—      fc- 


<  .  J 

O  -  ^ 

•  i:  O 

CO  X  fa 

<  ?  5 


—  tt 


01        '* 


A 


-,5 


5^1 


CO 


348 


THE  MECHANICAL  EQUIPMENT 


l! 


»' 


ciple.     The   upright   portion   of   this   machine   is   a 
specialized  form  of  the  vertical  slotter  described  on 
page  000.     In  fact,  it  will  be  seen  that  the  slotter 
illustrated  in  Figure  97  might  be  rigged  up  to  per- 
form the  functions  of  this  tool.  The  column  is  mounted 
on  a  long  base  plate,  a,  and  may  be  moved  in  and  out 
to  accommodate  different  diameters  of  gears.     The 
gear  blank  is  supported  on  an  arbor,  b,  on  a  rotating 
table,  which  is  indexed  by  a  worm  and  a  worm  wheel 
operated  through  change  gears  by  an  electric  motor 
provided  for  that  purpose.     The  machine  is   large 
enough  to  swing  work  forty  feet  in  diameter.  The  tem- 
plates for  shaping  the  tooth  outline  are  mounted  in 
brackets,  c,c,  on  the  tool  head  on  either  side  of  the  tool 
post.  The  tool  post  is  pressed  tow^ard  the  right-  or  left- 
hand  former  by  a  spring,  as  may  be  required,  and  is 
provided  with  a  feeding  mechanism  for  moving  it  out- 
ward.   It  is  thus  used  to  reproduce  the  outline  of  the 
template  and  to  form  each  side  of  a  space  between  two 
teeth.    This  type  of  machine  is  used  for  coarse-pitch 
gears  that  are  too  large  to  be  cut  by  a  formed  tool.    It 
has  the  advantage  over  the  formed  cutter  process  of 
being  comparatively  simple  in  operation  and  adapt- 
able to  special  w^ork;  gears  of  this  size  are  never 
made  in  quantity. 

Fellows  Gear-Shaper. — The  Fellows  gear-shaper, 
shown  in  Figures  125  and  126,  is  a  successful  appli- 
cation of  the  form-generating  method.  Figure  125 
shows  three  gear  blanks  mounted  on  the  work  spindle. 
The  cutter  has  the  form  of  a  complete  gear,  and  is 
carried  on  the  end  of  a  reciprocating  vertical  ram 
or  slide,  a,  in  the  saddle,  b.    The  saddle  is  adjustable 


348 


THE  MRC4IA\l(^\Ti  h:Q(  II>A1K\T 


Ik 


(']j)](\      Tlio    ii])ri<;'lit    poi'tioH    of    tliis    inacliinc    is    a 
six'cializod   form  of  tho  vortical   slottor  doserihod  on 
]}i\iro  ()()().     In   fact,  it   will   1h»  scon   that  the  slotter 
illustrat(Ml  in  Fignro  07  nii.i»lit  he  i-iggcd   np  to  per- 
form tin*  fnnclions  of  this  tool.  Tin*  column  is  mounted 
on  a  lon,ti,'  hasc  plate,  a,  and  may  he  moved  in  and  out 
to   accommodate   different   diameteis   of  .i»ears.     TIk^ 
.U'cai-  hiank  is  supported  on  an  arhor,  h,  on  a  rotatinij; 
tahle,  whicli  is  indexed  hv  a  worn)  and  a  worm  wheel 
o[)erated  tlirongh  clian<;e  gears  hy  an  electric  motor 
provided   for    that    purpose.      The    machine*    is    lar^-e 
enou,<;h  to  swin.!*'  work  forty  feet  in  diameter.  The  tem- 
plates for  shaj)in.i;-  the  tooth  outline  an*  mounted  in 
l)!-ackets,  c,c,  on  the  tool  head  on  either  side  of  the  tool 
post.  The  tool  post  is  pressed  towarci  the  right-  or  left- 
hand  foinier  hy  a  spring,  as  may  he  recpiired,  and  is 
I)r()vided  with  a  feeding  mechanism  for  moving  it  out- 
ward.   It  is  thus  nsed  to  reproduce  the  outline  of  the 
template  and  to  form  each  side  of  a  space  hetween  two 
teeth.    This  ty])e  of  machine  is  used  for  coarse-|)itch 
gears  that  are  too  large  to  ])e  cut  hv  a  formed  tool.    It 
has  the  advantage  over  the  formed  cutter  process  of 
heing  compai'atively  sim])le  in   operation  and  adapt- 
ahl(»   to   special    work;   gears   of   this  vsize   are   never 
made  in  quantity. 

Fellows  Gear-Shaper. — The  Fellows  gear-shaper, 
shown  in  Figures  12-")  and  12(),  is  a  successful  appli- 
cation of  the  form-generating  method.  Figure  125 
sliows  tliree  gear  l)lanks  mounted  on  the  work  spindle. 
The  cutter  has  the  foi'm  of  a  eomph'te  gear,  and  is 
carried  on  the  end  of  a  reciprocating  vertical  ram 
or  slide,  a,  in  the  saddle,  b.    The  saddle  is  adjustable 


r7 


350 


THE  MECHANICAL  EQUIPMENT 


sidewise  to  accommodate  work  of  different  diameter, 
and  the  stroke  of  the  ram  is  adjustable  to  suit  dif- 
ferent widths  of  face  on  the  work  to  be  cut.  The 
action  of  the  machine  is  as  follows: 

The  saddle  with  the  cutter  is  withdrawn  from  the 
work  spindle,  and  the  blanks  are  set  in  place.    With- 
out rotating  either  the  cutter  or  the  work,  the  head 
is  fed  inward  toward  the  center  of  the  blank.    This 
feed  is  continued  until  the  cutter  has  cut  its  way 
into  the  blank  to  the  proper  depth.    The  inward  feed 
is  then  stopped,  and  the  cutting  tool  and  the  blanks 
are  rotated  slowly  at  the  same  pitch  velocity.     The 
rotation  takes  place  intermittently  at  the  end  of  each 
stroke  of  the  cutter.    As  this  action  is  continued,  the 
cutter  will  gradually  generate  the  teeth  around  the 
surface  of  the  blank  until  the  gear  is  finished.     An 
adjustable  stop,  c,  is  shown  on  the  side  of  the  head, 
which  is  set  down  against  the  side  of  the  gear  or  the 
supporting  device  and  locked  in  position.     The  stop 
takes  the  reaction  of  the  cut,  and  relieves  the  driving 
mechanism  of  any  tendency  to  spring.     The  cutting 
stroke  is  usually  upwards,  so  that  it  forms  a  draw  cut 
— the  thrust  taken  up  by  the  stop.    The  cutter  may  be 
reversed  and  work  on  the  downward  stroke  when  it 
is  necessary  to  plane  into  a  recess,  as  in  automobile 
transmission  gears.    This  type  of  machine,  which  is 
used  for  medium-sized  gears,  produces  very  accurate 
work.     The  sides  of  the  cutter  are  relieved  so  that 
the  tool  may  be  ground  on  its  upper  face  without 
losing  the  correct  shape,  and  the  cutter  is  trued  up 
by  grinding  after  it  is  hardened,  by  the  process  illus- 
trated in  C,  Figure  120. 


GEAR-CUTTING 


351 


Hobbing^  Machines. — The  form-generating  principle 
may  be  used  for  machines  of  the  milling  type  as 
well  as  for  those  of  the  shaper  type.  A  case 
in  point  is  the  bobbing  process.     Figure  127  shows 


>ri 


m 


^ Upper  IndcK  Worm-g 


Saddle 


^Upper  Index 
Whetl 


FIG.   126.      SECTION  OF  GEAR  SHAPER  HEAD 
Fellows  Gear  Shaper  Co. 


GEAR-CUTTING 


353 


an  automatic  bobbing  machine  that  may  be  used  for 
cutting  either  spur,  helical  or  worm  gears,  according 
to  the  angle  at  which  the  cutter  head,  a,  is  set.  The 
cutting  tool  used  is  a  **hob,"  (see  a.  Figure  99),  a 
special  type  of  formed  milling  cutter,  in  which  the 
teeth  are  shaped  and  relieved,  as  in  Figure  122,  but 
are  arranged  in  a  helix,  like  a  screw  thread,  instead 
of  in  a  circle.  Every  one  has  noticed  how  a  screw 
thread  appears  to  travel  along  its  axis  as  the  screw 
is  revolved.  If  the  hob  is  mounted  on  the  spindle,  b, 
and  the  axis  is  tipped  up  at  an  angle  equal  to  the 
helix  angle,  the  cutting  motion  of  the  edges  will  be 
parallel  to  the  axis  of  a  gear  blank  mounted  on  the 
arbor,  c;  the  action  of  the  edges  will  have  the  same 
effect  as  that  of  the  milling  cutter  in  C,  Figure  120, 
as  it  moves  past  the  face  of  the  blank.  In  operation, 
the  gear  blanks  mounted  on  the  arbor,  are  first  fed 
inward  toward  the  cutting  tool,  and  are  rotated 
by  a  power  feed  meantime,  in  order  that  they  may 
have  the  rolling  action  required.  When  the  proper 
depth  of  cut  is  reached,  the  cutting  head  is  given  a 
gradual  downward  feed  across  the  face  of  the  gears 
until  the  work  is  completed.  In  some  respects  this 
type  of  machine  is  better  than  the  ordinary  one 
shown  in  Figures  121  and  123,  since  a  greater  num- 
ber of  teeth  are  cutting  at  once,  but  absolute  rigidity 
is  more  important  in  this  type  and  the  motions  are 
more  difficult  to  control. 

Cutting  Helical  Gears. — Helical  gears  may  be  cut 
by  either  the  shaping  or  the  milling  process.  The 
Fellows  gear-shaper,  shown  in  Figures  125  and  126, 
may  be  used  to  cut  them.    If  the  Fellows  machine  is 


III 


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.'111  (intonmtic  lioUhini;-  niacliinc  that  may  he  used  for 
('iittiii.u-  cithcM-  spur,  hi^lical  oi*  worm  ^^ears,  according 
to  the  aiii;lc  at  which  tlic  cutter  head,  a,  is  set.  The 
(•uttiu,i>-  tool  used  is  a  'Mioh,"  (see  a.  Figure  90),  a 
sjxH'ial  type  ot*  formed  milling  cutter,  in  wiiich  the 
te(*th  are  shaped  and  relieved,  as  in  Figure  12:^,  but 
ai-e  arranged  in  a  helix,  like  a  screw  thread,  instead 
of  in  a  circle.  Evei'v  one  has  noticed  how  a  screw 
thread  a|)peais  to  ti'avel  along  its  axis  as  the  screw 
is  revolved.  .11*  the  hoh  is  mounted  on  the  spindle,  b, 
and  the  axis  is  tipped  up  at  an  angle  equal  to  the 
helix  angle,  the  cntting  motion  of  the  edges  will  be 
parallel  to  the  axis  of  a  gear  blank  mounted  on  the 
arbor,  c:  the  action  of  the  edges  will  have  the  same 
elTect  as  that  of  the  milling  cuttei*  in  C,  Figure  120, 
as  it  moves  past  the  face  of  the  blank.  In  operation, 
the  geai'  blanks  mounted  on  the  arbor,  are  first  fed 
inwai'd  toward  the  cutting  tool,  and  are  rotated 
hy  a  ])ower  feed  meantime,  in  order  that  they  may 
have  the  i-olling  action  re<piired.  WIhmi  the  proper 
depth  of  cut  is  reached,  the  cutting  head  is  given  a 
gradual  downward  feed  across  the  face  of  the  gears 
until  the  work  is  com|)leted.  In  som(^  r(^<pects  this 
type  of  machine  is  better  than  the  ordinarv  one 
shown  in  Figures  121  and  12o,  sinc(^  a  greater  nnm- 
hc?"  of  teeth  ar(^  cuttini»-  at  once,  but  absolute  rigidity 
is  more  impoi'tant  in  this  type  and  the  motions  are 
more  difficult  to  control. 

Cutting'  Helical  Gears.  Helical  g(»ais  inay  be  cut 
by  either  tlu'  shaping  or  the  milling  })f•oc(^^s.  Tln^ 
l^'ellows  gear-shapei-,  shown  in  Figures  12.")  and  12(>, 
niay  be  used  to  cut  tlirm.     \{  the  Fellows  machine  is 


T' 


354  THE  MECHANICAL  EQUIPMENT 

used,  the  cylindrical  guide,  k,  in  Figure  126,  is  given 
an  additional  rotary  motion  by  means  of  the  helical 
cam  surface,  a.  Figure  128,  which  has  the  same  lead 
as  the  helix  of  the  cutter,  b,  at  the  other  end  of  the 
shaft,  c.  The  camming  action  of  the  surface,  a,  on  a 
fixed  pin,  not  shown,  gives  the  cutter  the  correct 
helical  motion  required.  The  bobbing  machine.  Fig. 
nre  127,  may  be  used  to  cut  helical  gears;  the  head 
may  be  set  around  so  that  the  teeth  of  the  hob  will 
move  past  the  pitch  surface  of  the  gear  blanks  at  the 
required  helical  angle,  and  the  rotary  feed  of  the 
blanks  may  be  suitably  adjusted.  In  other  respects, 
the  action  of  the  machine  is  the  same  as  for  cutting 
straight  teeth.  If  the  axis  of  the  cutting  hob  is  set 
horizontal,  the  machine  may  be  used  to  cut  a  worm 
gear. 

Cutting  Bevel  Gears.— Figure  129  shows  a  machine 
that  is  used  to  cut  bevel  gears  according  to  the 
formed-cutter  method.  In  many  respects  it  is  like 
the  machine  shown  in  Figure  121,  but  the  slide,  a, 
Figure  129,  carrying  the  cutters  (not  shown)  is  in  this 
case  provided  with  an  angular  adjustment,  b,  in  the 
vertical  plane,  to  give  a  feed  along  the  pitch  cone. 
The  action  of  the  machine  is  similar  in  other  respects 
to  the  spur-gear  cutter— if  the  saddle  is  dropped  to 
a  horizontal  position,  it  may  be  used  for  spurs. 

Figure  130  shows  a  bevel-gear  cutting  machine  that 
embodies  an  application  of  the  former,  or  template, 
principle  illustrated  in  Figure  117.  The  blank  is 
mounted  on  a  horizontal  indexing  arbor,  a.  The  cut- 
ting tool,  b,  is  carried  in  a  shaper  head  sliding  on  a 
carriage,  c,  which  has  a  horizontal  angular  adjust- 


GEAR-CUTTING 


f;r; 


PIG.    129.      AUTOMATIC   BEVEL-GEAR   MILLING    MACHINE 

Brown  &  Sharpe  Mfg.  Co. 

ment  so  that  it  may  be  set  parallel  to  the  side  of  the 
theoretical  pitch  cone  of  the  bevel  gear  to  be  cut. 
In  the  view  shown,  it  is  seen  nearly  **end  on,"  and 
the  stroke  of  the  tool-carrying  head  is  forward  along 
the  sliding  surface,  c.  The  path  of  the  cutting  tool, 
b,  as  it  is  slowly  fed  in  toward  the  center  of  the  blank 


.>^k 


354  THE  MECHANICAL  EQL'llWlENT 

used,  the  cylindrical  guide,  k,  in  Figure  126,  is  given 
an  additional  rotary  motion  by  means  of  the  helical 
cam  surface,  a.  Figure  128,  wliicli  lias  the  same  lead 
as  the  helix  of  the  cutter,  h,  at  the  other  end  of  the 
shaft,  c.  The  camming  action  of  the  surface,  a,  on  a 
fixed  pin,  not  sliown,  gives  tlie  cutter  the  correct 
helical  motion  re(iuired.  The  hobhing  nuichine.  Fig- 
ure 127,  may  be  used  to  cut  helical  gears;  the  head 
may  be  set  around  so  that  the  teeth  of  the  hob  will 
move  past  the  pitch  surface  of  the  gear  blanks  at  the 
required  helical  angle,  and  the  rotary  feed  of  the 
blanks  may  ])e  suitably  adjusted.  In  other  respects, 
the  action  of  the  machine  is  the  same  as  for  cutting 
straight  teeth.  If  the  axis  of  the  cutting  hob  is  se't 
horizontal,  the  machine  may  be  used  to  cut  a  worm 
gear. 

Cutting  Bevel  Gears.— Figure  129  shows  a  machine 
that  is  used  to  cut  bevel  gears  according  to  the 
formed-cutter  method.  In  many  respects  it  is  like 
the  machine  shown  in  Figure  121,  but  the  slide,  a, 
Figure  129,  carrying  the  cutters  (not  shown)  is  in  this 
case  provided  with  an  angular  adjustment,  b,  in  the 
vertical  plane,  to  give  a  feed  along  the  pitch  cone. 
The  action  of  the  machine  is  similar  in  other  respects 
to  the  spur-gear  cutter— if  the  saddle  is  dropped  to 
a  horizontal  position,  it  may  l)e  used  for  spurs. 

Figure  130  shows  a  bevel-gear  cutting  machine  that 
embodies  an  application  of  the  former,  or  template, 
principle  illustrated  in  Figure  117.  The  blank  is 
mounted  on  a  horizontal  indexing  arbor,  a.  The  cut- 
ting tool,  b,  is  carried  in  a  shaper  head  sliding  on  a 
carriage,  c,  which  has  a  horizontal  angular  adjust- 


GEAK-crTTTNTJ 


:]:>:> 


FIG.    129.      AUTOMATIC    BE\'EL-r,EAR    MILLING     MACHINE 

Brown  &  Sharp<^  Mfjr.  Co. 

ment  so  that  it  may  be  set  parallel  to  the  side  of  the 
theoretical  pitch  cone  of  the  bevel  gear  to  be  cut. 
In  the  view  shown,  it  is  seen  nearly  *'end  on,''  and 
the  stroke  of  the  tool-carrying  head  is  forward  along 
the  sliding  surface,  c.  The  path  of  the  cutting  tool, 
b,  as  it  is  slowlv  fed  in  toward  the  center  of  the  blank 


i 


If 


iri 


GEAR-CUTTING 


357 


between  each  cutting  stroke,  is  controlled  by  the 
roller,  d,  corresponding  to  the  one,  B,  shown  in  Figure 
117.  Three  former  plates,  e,  f,  g,  are  mounted  on  the 
triangular  plate,  h.  The  first  one,  e,  on  which  the 
roller  now  rests,  is  straight,  and  is  used  for  a  plain 
roughing  cut  once  around,  which  removes  most  of  the 
stock  between  the  teeth.  The  plate,  h,  is  then  rotated 
one-third  of  a  turn,  and  the  former,  f,  is  used  to  fin- 
ish one  side  of  the  teeth.  When  this  has  been  done 
around  the  blank,  the  third  former,  g,  is  used  to 
finish  the  opposite  side  of  the  teeth. 

Machine  Embodying^  Form-Generating  Principle. — 
The  form-generating  principle  is  used  in  the  machine 
shown  in  Figure  131,  which  is  built  by  the  same  firm 
as  the  one  that  builds  the  machine  just  described. 
If  the  height  of  the  pitch  cone  of  a  bevel  gear  is 
shortened,  the  gear  grows  flatter  until  the  limit  is 
reached  in  one  of  zero  height,  in  which  the  teeth  are 
ranged  around  in  a  circle  on  a  pitch  surface  that  is 
a  plane.  Such  a  gear,  called  a  crown  gear,  bears  the 
same  relation  to  bevel  gears  that  the  rack  does  to 
spur  gears;  and  the  teeth,  like  those  of  a  rack,  have 
straight  sides.  Just  as  the  cutter,  T,  in  B,  Figure 
120,  replacing  the  side  of  an  imaginary  rack  tooth, 
may  be  used  to  generate  a  spur  tooth,  so  a  straight- 
sided  cutting  tool,  replacing  the  side  of  a  crown  gear 
tooth,  may,  when  properly  rolled  in  relation  to  a 
bevel  gear  blank,  be  used  to  cut  the  proper  tooth 
form.  The  gear  to  be  cut  is  shown  at  a.  Since  there 
are  two  cutters,  both  sides  of  a  tooth  are  finished  at 
once.  The  upper  cutter,  b,  is  shown  just  clear  of  the 
work;  the  lower  one  is  hidden.    Those  sectors  of  the 


mi 
I 


GKAU-CrTTLXG 


o57 


hotwoon  cacli  cutting'  strok(\  is  tduI rolled  hy  tlio 
rollor,  (1,  C'orrospondiii^-  to  tin  one,  1>,  shown  in  Figure 
117.  Tliree  lormoi-  plates,  e,  f,  g,  are  mounted  on  the 
triangular  plate,  h.  The  first  one,  e,  on  which  the 
roller  now  rests,  is  straight,  and  is  used  for  a  plain 
roughing  cut  once  around,  which  removes  most  of  the 
stock  between  the  teeth.  The  plate,  h,  is  then  rotated 
one-third  of  a  turn,  and  the  former,  f,  is  used  to  fin- 
ish one  side  of  the  teeth.  AVhen  this  has  been  done 
around  the  ])lank,  the  third  former,  g,  is  used  to 
finish  tlie  opposite  side  of  the  teeth. 

Machine  Embodying  Form-Generating  Principle. — 
The  t'oi'm-gcMierating  j)rincii)le  is  used  in  the  machine 
sliown  in  P'igure  131,  which  is  l)uilt  l)y  the  same  firm 
as  the  one  that  builds  the  machine  just  described. 
If  the  heiglit  of  the  pitch  cone  of  a  bevel  gear  is 
shortened,  the  gear  grows  flatter  until  tlie  limit  is 
reached  in  one  of  zero  heiglit,  in  which  the  teeth  are 
ranged  around  in  a  circle  on  a  pitch  surface  that  is 
a  plane.  Such  a  gear,  called  a  crown  gear,  bears  the 
same  relation  to  bevel  gears  that  the  rack  does  to 
spur  gears;  and  the  teeth,  like  those  of  a  rack,  have 
straight  sides.  Just  as  the  cutter,  T,  in  B,  Figure 
120,  replacing  the  side  of  an  inmginary  rack  tooth, 
?uay  be  used  to  generate  a  spur  tooth,  so  a  straight- 
sided  cutting  tool,  replacing  the  side  of  a  crown  gear 
tooth,  nuiy,  when  properly  rolled  in  relation  to  a 
bevel  gear  blank,  be  used  to  cut  the  proper  tooth 
form.  The  gear  to  l)e  cut  is  shown  at  a.  Since  there 
are  two  cutters,  l)oth  sides  of  a  tooth  an»  finished  at 
once.  The  ui)per  cutter,  b,  is  sliown  just  clear  of  the 
work;  the  lower  one  is  hidden.     Tliose  sectors  of  the 


GEAR-CUTTING 


359 


crown  gear  and  the  master  gear  which  are  control- 
ling the  motion  are  seen  at  c  and  d. 

The  same  firm  has  developed  a  machine  for  gener- 
ating with  a  milling  cutter  a  bevel  gear  that  corre- 
sponds to  the  helical  spur  gear.  In  this  gear  the 
teeth  are  curved  on  the  arc  of  a  circle. 

There  are  so  many  types  of  gear-cutting  machines 
that  it  is  impossible  to  consider  all  of  them  here; 
enough  have  been  shown,  however,  to  illustrate  the 
more  general  principles  involved. 


II 


GEAR-CUTTJNG 


850 


crown  gear  and  the  master  gear  whicli  are  control- 
ling the  motion  are  seen  at  c  and  d. 

The  same  firm  has  developed  a  machine  lor  gener- 
ating with  a  milling  cutter  a  bevel  gear  that  corre- 
sponds to  the  helical  spur  gear.  In  this  gear  the 
teeth  are  curved  on  the  arc  of  a  circle. 

There  are  so  many  types  of  gear-cutting  machines 
that  it  is  impossible  to  consider  all  of  them  here; 
enough  have  been  shown,  however,  to  illustrate  tlu* 
more  general  principles  involved. 


I;   I 


SCREW-THREAD-CUTTING 


361 


'I!  If 


i   1 1 
11 


I 


(  '. 


f    ! 
1    1 

(! 


CHAPTER  XX 
SCEEW-THEEAD-CUTTING 

Early  Methods  of  Cutting  Screw  Threads.— Screw- 
thread-cutting,  like  gear-cutting,  is  one  of  the  funda- 
mental  operations  found  in  every  machine  shop,  how- 
ever crude.    The  early  screws  were  large,  and  made 
of  wood,  because  such  screws  could  be  *^ chased"  by 
hand  on  the  rough  speed  lathes  then  used.    The  first 
metal  screws  were  formed  by  means  of  hardened  dies 
of  the   crudest   kinc^,   without   cutting  edges,   which 
were  turned  and  forced  onto  the  bar  to  be  threaded. 
Ihey   were,    of   course,   wretchedly   inaccurate,    and 
many  attempts  were  made  to  originate  threads  with 
some  pretense  to  accuracy.    Many  of  these  early  at- 
tempts were  very  ingenious;  in  one  instance,  two  wires 
side  by  side  were  wound  around  the  bar  and  soldered 
to  It.    One  of  them  was  then  removed,  leaving  a  space 
between  the  coils  of  the  other,  and  forming  a  screw 
thread. 

Another  method  was  to  chase  the  thread  with  a 
cutting  tool,  which  was  fed  forward  by  a  knife-like 
edge  held  against  the  work  at  the  required  thread 
angle  and  allowed  to  run  freely,  carrying  the  cutting 
tool  with  it  as  the  work  was  revolved.  This  method 
was  better,  and  it  was  the  one  used  by  Maudslay  in 
generating  the  lead-screw  threads  for  his  first  lathes 
The  invention  of  the  slide-rest  soon  led  to  the  de- 
velopment  of  the  lead  screw  and  the  screw-cutting 

360 


lathe.  As  pointed  out  elsewhere,  Maudslay  at  first 
used  a  different  lead  screw  for  each  size  of  thread, 
but  he  soon  developed  the  combination  of  a  single 
lead-screw  with  change  gears  to  vary  its  speed  in 
relation  to  the  work;  this  is  used  today. 

Standardization  of  Screw  Threads. — There  is  no 
detail  in  machine  construction  in  which  standardiza- 
tion is  more  essential  than  in  connection  with  screw 
threads.  We  are  so  used  to  standard  practice  in  this 
respect  that  the  modern  mechanic  does  not  realize 
the  chaos  that  existed  in  the  early  machine  shops. 
Every  nut  had  to  be  fitted  to  its  respective  bolt,  and 
both  were  marked  in  order  that  they  might  be  iden- 
tified if  they  were  taken  apart.  The  first  attempt  at 
standardization  was  made  by  Maudslay,  who  settled 
upon  a  set  of  standard  taps  and  dies  for  use  in  his  own 
shop.  Joseph  Clement,  a  mechanic  who  worked  for 
Maudslay,  took  up  his  work,  standardized  it  still 
further,  and  began  manufacturing  it  for  the  market. 
Joseph  Whitworth,  who  worked  for  both  Maudslay 
and  Clement,  standardized  the  screw-thread  practice 
of  England,  and  in  1841  brought  out  what  is  still 
known  as  the  *' Whitworth  thread." 

Types  of  Screw  Threads. — Since  screw  threads  are 
used  for  a  wide  variety  of  purposes,  it  is  not  possible 
to  standardize  them  completely,  but  standardization 
has  been  made  to  the  extent  of  reducing  them  to  a 
few  well-known  types,  which  are  differentiated  partly 
by  their  use  and  partly  by  their  historical  origin. 

The  simplest  thread  is  the  V-thread,  a  cross-section 
of  which  is  shown  at  A,  in  Figure  132.  This  is  formed 
by  straight  sides,  which  are  on  an  angle  of  60  degrees 


1 "  J 


'i 


I 


III 


1     ;  ■   ( 


362 


THE  MECHANICAL  EQUIPMENT 


A-  V- THREAD 


014P 


B-  US.  STANDARD 


C  -WHITWORTH 


r    Pitch.  P — ^ 
JhU7/H 


D  *  SQUARE  THREAD 


E  -  ACME  STANDARD 


FIG.  132.     SECTIONS  OP  STANDARD  SCREW  THREADS 

to  each  other,  and  which  have  sharp  corners  at  top 
and  bottom.     This  thread  is  the  simplest  to  make, 
but  It  has  many  disadvantages.    The  sharp  point  on 
^e  outer  end  of  the  thread  is  easily  bruised,  while 
the  sharp  corner  at  the  root  of  the  thread  weakens 
the  bolt  greatly,  and  is  difficult  to  maintain  on  ac- 
count of  the  wearing  of  the  point  of  the  tool  that 
makes  the  cut.    This  form,  however,  is  well  adapted 
to  the  making  of  pressure-tight  joints  and  in  slightly 
modified  form,  is  the  basis  of  the  Briggs   thread, 
which  IS  standard  for  pipes  and  pipe  fittings.     This 
IS  almost  its  only  commercial  use. 

.J^^  F""'*^"^  ^^^^^^  standard  thread,  B,  is  similar  to 
the  V-thread,  except  that  the  top  and  the  bottom  are 
flattened  for  a  distance  equal  to  one-eighth  of  the  pitch. 
The  depth  is  therefore  three-quarters  that  of  the  cor- 


SCRBW-THREAD-CUTTING 


363 


responding  V-thread.  This  standard  was  developed 
by  William  Sellers,  of  Philadelphia,  in  1864,  and 
is  the  one  most  widely  used  in  the  United  States. 
It  is  less  liable  to  injury  than  the  V-thread,  and  is 
much  stronger.  The  tools  for  cutting  it  are  quite 
as  easily  made,  and  much  more  easily  maintained. 

The  standard  thread  used  in  England  is  the  Whit- 
worth  thread,  C,  the  sides  of  which  have  an  angle 
of  55  degrees  instead  of  60;  the  top  and  bottom  are 
rounded  instead  of  flat.  In  some  respects  this  thread 
is  better  than  the  United  States  standard,  as  it  has 
no  sharp  corners  and  wears  well;  it  is  not,  however, 
so  easy  to  originate.  The  metric  screw  thread  used 
on  the  continent  of  Europe  was  adopted  in  1898  by  an 
international  congress  which  studied  all  the  standards 
then  in  existence.  This  thread  is  similar  to  the 
United  States  standard,  but  a  slight  clearance  is  per- 
mitted, which  is  obtained  by  rounding  the  corner  at 
the  root  of  the  thread. 

All  of  these  standards  have  not  only  a  specified 
cross-section,  but  a  definite  number  of  threads  per 
inch  for  each  size  of  bolt.  The  United  States  stand- 
ard has  larger  threads  for  small  screws  than  has  been 
found  the  best  in  practice.  An  additional  standard 
has  therefore  sprung  up,  known  as  the  S.  A.  E.  stand- 
ard, for  the  smaller  sizes,  which  conforms  to  the 
shape  of  the  United  States  thread,  but  contains  more 
threads  per  inch. 

In  all  these  standards  the  angle  between  the  sides 
of  the  thread  is  55  or  60  degrees.  An  angle  as  steep 
as  this  produces  a  considerable  side  thrust  on  the 
nut,  which  increases  the  friction.    When  the  threads 


364 


(ii 


I!  ;;'!l 


'■r 


THE  xMECHANICAL  EQtnPMENT 


SCREW-THREAD-CUTTING 


365 


are  nsed  for  holding-down  purposes— as  in  the  case 
of  bolts  and  nuts,  this  friction  is  an  advantage.  When 
the  thread  is  used  to  transmit  running  motion,  fric- 
tion IS  a  detriment;  hence,  square  threads,  as  shown  in 
D,  were  developed  for  this  purpose.  In  these,  the 
space  and  the  tooth  have  the  same  thickness.  Such 
threads  are  little  more  than  half  as  strong  as  United 
States  threads,  and  cannot  be  cut  in  dies. 

For  transmitting  motion  intermittently— as  in  the 
traversing  of  a  lathe  carriage  by  the  lead-screw- 
the  nut  IS  made  in  halves,  to  be  clamped  on  the 
thread  when  desired.    For  such  a  purpose,  the  square 
thread  is  difficult  to  enter,  and  has  no  take-up  for 
wear.      To    overcome    these    difficulties,    the    Acme 
Standard  thread,  shown  at  E,  is  now  generally  used. 
The  angle  between  the  sides  of  this  thread  is  29  de- 
grees,  and  the  flat  place  at  the  top  is  about  one- 
third  of  the  pitch.     The  widths  of  the  thread  and 
the  space  are  equal  at  a  point  midway  of  their  height. 
This   thread   is   a  compromise   between   the   United 
States  and  the  square  thread,  and  is  generally  used 
for  lead  screws  and  other  forms  of  working  screw. 
It  is  stronger  than  the  square  thread,  allows  take-up 
for  wear,  is  easily  clamped  by  a  split  nut,  and  may 
be  cut  by  ordinary  taps  and  dies. 

Other  forms  of  threads  are  used  for  special  pur- 
poses, but  need  not  be  considered  here. 

Cutting  Screw  Threads.— Modern  methods  of  cut- 
ting screw  threads  are:  first,  by  means  of  taps  and 
dies,  operated  by  hand  or  in  a  machine;  second,  by 
means  of  lathe  and  lead  screw;  third,  by  cam  control 
in  automatic  turret  lathes;  and  fourth,  by  milling. 


For  thread-cutting,  the  first  method  is  used  more 
than  any  other.  Hand  taps  and  dies  are  described 
and  illustrated  in  Chapter  XII.  For  light  special 
work  and  for  rough  outside  work — such  as  construc- 
tion work,  country  blacksmithing,  etc.— these  are 
used  in  holders  provided  with  two  handles.  For  the 
smaller  sizes  of  screw  threads,  the  taps  must  be  solid; 
they  are  practically  like  those  illustrated  in  Figures 
42  and  43. 

In  the  larger  sizes  of  taps,  which  are  used  with 
machines,  the  cost  of  making  the  entire  tool  of  tool 
steel  would  be  prohibitive,  so  the  cutters  are  made 
separate  and  inserted  in  the  body.  This  method  has 
a  further  advantage  in  that  the  cutters  may  be  set 
out  to  allow  for  wear.  A  great  variety  of  taps  and 
dies  has  been  developed  for  use  on  the  various  ma- 
chine tools  that  do  threading  work. 

Bolt-Threading  Machines.— The  machines  most  used 
for  this  purpose  are  the  drill  press  and  the  turret 
lathe,  both  hand  and  automatic  types.  Drill  presses 
that  are  used  for  this  work  are  equipped  with  change- 
gear  feeds  to  give  the  spindle  a  lead  corresponding 
to  that  of  the  thread  to  be  cut.  The  holder  which 
carries  the  tap  may  be  equipped  with  a  friction  drive 
which  slips  if  the  tap  sticks  or  strikes  the  bottom  of 
the  hole.  Drill  presses  are  also  fitted  with  an  auto- 
matic reverse  on  the  drive,  which  may  be  set  for  a 
certain  depth,  so  that  when  the  tap  has  reached  this 
point  the  spindle  is  reversed  and  the  tap  is  backed 
out.  The  drill  press  is  generally  used  for  tapping, 
or  threading,  rough  holes,  such  as  those  used  for  stud 
bolts  in  valves,  fittings,  and  general  machinery. 


i* 


I' 


366 


■f 
1 1.1 


m 


!■'  'Ii 


'^   ll 


!'     -i,   I 


J,   f 


f 

1 
1 

1          * 

i  ■ 

I 

THE  MECHANICAL  EQUIPMENT 


fW.  -?'^  "•''  ^,  ''^'"  produced  in  quantities,  are 
threaded  in  a  bolt-threading  machine,  such  as  that 
shown  m  Figure  133.  which  is  specially  designed  for 
this  purpose.  Machines  of  this  character  have  a 
power-driven  spindle  that  carries  the  threading  die, 
a;  the  bolt,  b,  to  be  threaded,  is  carried  in  a  s^table 
holder,  c,  mounted  on  the  slide,  d,  which  is  free  to 

ZIL"^  ""*•  7^'^'^  ^'^^'  «'  *hich  does  the 

threading  is  opened  and  closed  by  a  trip  rod,  e,  pro- 
vided with  two  adjustable  stops.  One  of  these  kops, 
operated  by  the  in-and-out^motion  of  the  slide,  is  set 
to  open  the  die  when  the  bolt  has  been  threaded  the 
required  length;  thus  it  is  possible  to  withdraw  the 
work  quickly  without  reversing  the  machine.  When 
the  carriage  has  moved  backward,  the  other  stop 
closes  the  head  and  is  ready  to  cut  the  next  bolt. 

Opemi^  Die  Heads—There   are  many  types   of 
opening  die  heads  used  on  machines  of  this  style  and 

;^/°'r!;f*  ^  v5f'-     ^"«  °f  *!»«««  is  shown  in  Figure 
134     The  sliding  cutters,  or  chasers,  a,  of  carbon  or 
high-speed  steel,  are  clearly  shown  on  the  face  of 
the  die.    They  are  held  in  correct  register  with  each 
other  by  a  spline,  or  key,  b,  on  the  side.    The  first 
few  threads  of  the  cutters  are  ground  away  at  c  in 
order  that  the  work  of  cutting  may  be  distributed 
over  several  teeth  instead  of  being  concentrated  on 
the  first  tooth,  as  would  be  the  case  if  the  full  sec- 
tion were  retained.    The  middle  section  of  the  die 
d,  carries  on  the  side  next  the  cutters  four  proiect- 
ing  spiral  cams,  e,  one  for  each  cutter,  which  engage 
corresponding  notches,  f,  in  the  rear  edge  of  the  cut- 
ters.   When  the  handle,  g,  is  pulled  down,  these  pro- 


FIG.    iSS.      BOLT-THREADING    MACHINE 

367 


''^4 


366 


THE  MRf'HANICAL  EQUIPMENT 


Studs  or  bolts,  when  produced  in  quantities,  are 

w„  t  P-  '  ''t^'""''"^  rnachine,\uch  as  that 
shoun  m  l.,s„re  133,  which  is  specially  designed  for 
this  purpose.  Machines  of  thi;  chai-acter  W  a 
power-driven  spindle  that  carries  the  threading  die 
a;  the  Mt,  b,  to  be  threaded,  is  carried  in  a  sJtable 
holder,  c,  mounted  on  the  slide,  d,  which  is  free  to 

tTZw'"  ""*•    ?^'  ^''  ^^^'''  •''  ^^■'"'^h  does  the 

h  eading  is  opened  and  closed  by  a  trip  rod,  e,  pro- 
xided  w,th  two  adjustable  stops.  One  of  these  ^tops, 
operated  by  the  an-and-out-motion  of  the  slide,  is  set 
to  open  the  die  when  the  bolt  has  been  threaded  the 
required  length;  thus  it  is  possible  to  withdraw  the 
work  quickly  without  reversing  the  machine.  When 
the  carnage  has  moved  backward,  the  other  stop 
closes  the  head  and  is  ready  to  cut  the  next  bolt. 

Opemng  Die   Heads.-There   are   many   types    of 
opening  die  heads  used  on  machines  of  this  st^ie  and 

;i     ^f     r5- '•     ^"'  "^  ^^'''^  ''  «^°^^"  i"  "Figure 
l-\   ^''^'''^'"g  <^»«ers,  or  chasers,  a,  of  carbon  or 
high-speed  steel,  are  clearly  shown  on  the  face  of 
the  die.    They  are  held  in  correct  register  with  each 
other  by  a  spline,  or  key,  b,  on  the  side.    The  first 
few  threads  of  the  cutters  are  ground  away  at  c  in 
order  that  the  work  of  cutting  may  be  distributed 
over  several  teeth  instead  of  being  concentrated  on 
the  first  tooth,  as  would  be  the  ease  if  the  full  sec- 
tion were  retained.     The  middle  section  of  the  die 
_d,  carries  on  the  side  next  the  cutters  four  proiect- 
mg  spiral  cams,  e,  one  for  each  cutter,  which  eno-ao-e 
corresponding  notches,  f,  in  the  rear  edge  of  the'cirt- 
ters.    W  hen  the  handle,  g,  is  pulled  down,  these  pro- 


f,'t 


FiG.    133. 


BOLT-THRE.\DIXG    MACHINE 
3G7 


llfll  I 


SCREW-THREAD-CUTTING 


369 


FI^S.  134  AND  135 


COLLAPSING  DIE  HEAD   AND  COLLAPSING  TAP 
Geometric  Tool  Co. 
368 


jectioiis  cam  the  cutters  into  the  working  position. 
The  die  opens  automatically  by  simply  stopping  the 
forward  travel  of  the  die  when  the  desired  length  of 
thread  has  been  cut.  This  throws  the  cutters  back  so 
that  the  die  head  may  be  withdrawn  without  having 
to  be  unscrewed  from  the  work. 

The  cutters  may  be  thrown  in  again  by  using  the 
handle  or  by  having  a  steel  tripping-piece  strike 
the  pin,  g',  opposite.  They  may  be  adjusted  to  cut 
tight  or  loose  threads  by  means  of  the  adjusting 
screws,  h',  the  amount  of  adjustment  is  read  directly 
on  the  micrometer  scale,  i,  on  the  side  of  the  head. 
Roughing  and  finishing  cuts  may  be  taken  by  throw- 
ing the  lever,  j,  forward.  This  moves  the  cutters  out 
0.01  inch.  The  return  of  the  lever  to  its  backward 
position  closes  the  cutters  and  locks  them  in  position 
for  the  finishing  cut.  There  is  a  clear  hole  through 
the  center  of  the  die  head  and  the  shank,  somewhat 
larger  than  the  maximum  diameter  to  be  threaded, 
which  permits  threading  any  length  required. 

P'igure  135  shows  a  collapsing  tap  corresponding 
in  size  to  the  die,  Figure  134.  In  this  case,  the  cut- 
ters, a,  are  held  out  in  working  position  by  the  wedge, 
b.  When  the  proper  depth  has  been  reached,  the  face 
of  the  work  pushes  back  the  contact  plate,  c,  and 
releases  a  trip,  so  that  the  spring  withdraws  the 
wedge  and  allows  the  cutters  to  disappear  into  the 
holder.  There  are  a  great  many  collapsing  taps  and 
dies,  but  those  shown  are  sufficient  in  number  to  illus- 
trate the  principle  involved. 

Pipe-Threading  Machine.— Figure  136  shows  a  ma- 
chine for  threading  pipe.    In  this  machine  the  posi- 


4 


^k_ 


SCRKW-TUh'KAn-CrTTIXG 


309 


FIGS.  134  AND  135 


corj.APsixc;  die  ukad  and  collapsing  tap 
(Jeometric  Tool   Co. 
3GS 


jectioiis  cam  tlio  cutters  into  the  workiii.i;'  position. 
The  (lie  opens  automatically  hy  simply  stopi)ing  the 
forward  travel  oi*  the  die  when  the  desired  length  ol* 
thread  has  been  cut.  This  throws  the  cutters  hack  so 
that  the  die  head  may  be  withdrawn  without  having 
to  he  unscrewed  from  the  work. 

The  cutters  may  be  thrown  in  again  by  using  the 
handle  oi'  by  having  a  steel  tripping-])iece  strike 
the  pin,  g',  opposite.  They  may  be  adjusted  to  cut 
tight  or  loose  threads  by  means  oi*  the  adjusting 
screws,  h',  the  amount  of  adjustment  is  read  directly 
on  the  micrometer  scale,  i,  on  the  side  of  the  head. 
IJoughing  an<l  linishing  cuts  nuiy  be  taken  by  throw- 
ing the  lever,  j,  forward.  This  moves  the  cutters  out 
0.01  inch.  The  return  of  the  lever  to  its  backw^ard 
position  closes  the  cutters  and  locks  them  in  position 
for  the  linishing  cut.  There  is  a  clear  hole  through 
the  center  of  the  die  head  and  the  shank,  somewhat 
laruer  than  the  maxinuim  diameter  to  be  threaded, 
wdiich  permits  threading  any  length  required. 

Figure  13')  shows  a  collapsing  tap  corresponding 
in  size  to  the  die,  Figure  134.  in  this  case,  the  cut- 
ters, a,  are  held  out  in  working  position  by  the  wedge, 
b.  When  the  proper  dejith  has  been  reached,  the  face 
of  the  work  pushes  back  the  contact  plate,  c,  and 
n^leases  a  trip,  so  that  the  si)ring  withdraws  the 
wedge  and  allows  the  cutters  to  disappear  into  the 
holder.  There  are  a  great  many  collapsing  taps  and 
dies,  but  those  shown  are  sufficient  in  numl)er  to  illus- 
trate the  ])rincii)le  involved. 

Pipe-Threading  Machine.— Figure  LKi  shows  a  ma- 
chine for  threading  ])ipe.     In  this  nuudiine  the  posi- 


7/ 


\\ 


SCKEW-THREAD-CUTTING 


371 


tions   of  the  work  and  the  die  are   reversed  from 
those  shown  in  Figure  133.    Pipe  comes  in  lengths  of 
20   feet   or   more,   and   is   large   in   diameter.     The 
spindle,  a,  which  is  used  to  carry  the  work,  is  of 
east  iron,  long,  hollow,  and  large  enough  to  take  m 
the  maximum  size  to  which  the  machine  is  adapted. 
Clamping  jaws,  b,  provided  at  each  end  to  be  as  far 
apart  as  possible,  give  the  work  a  firm  support  and 
center  it  with  the  dies.    The  cutters,  c,  shown  mside 
the  die  head,  are  arranged  so  that  they  will  collapse 
into  the  head  when  the  thread  is  completed.    Special 
devices   are  provided  for  holding  short  lengths  ot 
pipe— such  as  nipples— and  extra  steps,  similar   to 
those  shown  at  d  on  the  rear  clamping  jaws,  are  used 
to  hold  pipe  flanges  for  threading. 

Thread-Cutting  on  Lathes.— While  nearly  all  com- 
mercial thread-cutting  is  done  in  dies,  special  threads 
wanted  singly  or  in  small  numbers  would  be  cut  on 
the  engine  lathe.  Long  and  accurate  threads,  also, 
such  as  those  required  for  the  various  machine  tool 
feeds— shown  in  the  foregoing  pages— are  cut  on 
lathes.  The  operation  is  a  skilful  one,  and  the  degree 
of  accuracy  obtainable  is  in  a  large  measure  con- 
trolled by  the  precision  of  the  lead  screw  that  is 
used.  Master  lead  screws  used  by  tool-builders  for 
cutting  their  own  product,  are  very  expensive  and 
have  to  be  handled  with  great  care. 

The  w,ork  is  mounted  on  the  lathe  centers,  and  a 
cutting  tool  that  has  a  cross-section  of  the  groove  be- 
tween the  threads,  is  mounted  in  the  tool  post.  The 
proper  change  gearing  is  used  which  will  give  the 
lead  required— or  distance  traveled  longitudinally  for 


SCKM'AVTIlKKADCrTTlNr! 


.»7  I 


lions    of    the    work    niirl    tlir    iVw    aiv    ivvrrscd    Irom 
liiose  shown  in  Figure  133.    Pipe  conies  in  lengths  ot 
20    feet    or    more,    and    is    large    in    diameter.      The 
si)indle,   a,  which   is   used   to   carry   the   work,   is   of 
cast  iron,  long,  hollow,  and  large  enough  to  take  in 
the  maximum  size  to  which  the  machine  is  adapted. 
Clamping  jaws,  b,  provided  at  each  end  to  be  as  tar 
apart  as  possi])le,  give  the  work  a  firm  support  and 
center  it  with  the  dies.     The  cutters,  c,  shown  mside 
the  die  head,  are  arranged  so  that  they  will  collapse 
into  the  head  when  the  thread  is  completed.    Special 
devices    are   provided    for   holding   short   lengths   of 
pipe—such   as   nipples— and   extra   steps,   similar   to 
those  shown  at  d  on  the  rear  clamping  jaws,  are  used 
to  hold  pipe  flanges  for  threading. 

Thread-Cutting  on  Lathes.— While  nearly  all  com- 
mercial thread-cutting  is  done  in  dies,  special  threads 
wanted  singly  or  in  small  numbers  would  be  cut  on 
the  engine  lathe.  Long  and  accurate  threads,  also, 
such  as  those  required  for  the  various  machine  tool 
feeds— shown  in  the  foregoing  pages— are  cut  on 
lathes.  The  operation  is  a  skilful  one,  and  the  degree 
of  accuracy  obtainable  is  in  a  large  measure  con- 
trolled by  the  precision  of  the  lead  screw  that  is 
used.  Master  lead  screws  used  by  tool-builders  for 
cutting  their  own  product,  are  very  expensive  and 
have  to  be  handled  with  great  care. 

The  work  is  mounted  on  the  lathe  centers,  and  a 
cutting  tool  that  has  a  cross-section  of  the  groove  be- 
tween the  threads,  is  mounted  in  the  tool  post.  The 
proper  change  gearing  is  used  which  will  give  the 
lead  required— or  distance  traveled  longitudinally  for 


/  -' 


372 


THE  MECHANICAL  EQUIPMENT 


m 


i  .:■ 


each  turn  of  the  screw  to  be  cut— and  a  light  cut 
with  the  point  of  the  tool  is  made  along  the  surface 
to  be  threaded.  The  tool  is  then  withdrawn  from  the 
work,  returned  to  its  starting  position,  and  fed  in  a 
httle  deeper  for  the  second  cut.  This  process  is  re- 
peated, and  each  time  the  tool  is  fed  in  a  little  more, 
until  the  proper  depth  has  been  reached.  Figure  35 
shows  a  tool-holder  with  a  separate  formed  cutter 
that  has  the  required  shape.  One  disadvantage  of 
^this  method  is  that  the  greatest  wear  comes  on  the 
point  of  the  tool,  which  can  least  afford  to  bear  it. 

Figure  137  shows  a  special  threading  tool  which 
has  been  developed  to  overcome  this  difficulty,  and 
which  simplifies  the  making  of  the  successive  cuts'. 
It  shows  an  application  of  the  turret  principle,  but 
it  is  used  on  the  carriage  of  a  standard  engine  lathe 
in  place  of  the  regular  tool  post.  It  consists  of  a  cut- 
ter with  ten  cutting  edges,  which  are  used  in  succes- 
sion. After  the  tool  has  been  set  to  cut  the  proper 
size,  the  first  of  these  cutting  edges,  a',  is  used  to 
make  the  first  cut.  The  handle  is  then  operated 
which  indexes  the  second  cutting  edge,  a^  into  po- 
sition.   This  makes  a  second  and  slightly  deeper  cut. 

All  the  cutting  edges  are  brought  into  action  suc- 
cessively, each  one  deepens  the  cut,  and  the  last  one 
brings  it  to  the  correct  size.  The  condition  of  the 
work  after  cuts  1,  5,  and  10  have  been  made,  is  shown. 
The  first  cutting  edges  have  broad  blunt  points— only 
the  last  one  or  two  need  have  sharp  points,  for  the 
cut  is  practically  completed  before  they  do  their  work. 
These  last  edges  therefore  retain  their  shape  for  a 
long  time.    The  sides  of  the  cutter  are  made  on  the 


AFTER  CUT  NO.  5 


AFTER  CUT  NO.  10 


FIG.  137.      INDEXING  THREADING  TOOL 

Rivett  Lathe  &  Grinder  Co. 

373 


Hi  ^"' 


hi! 

1.     'I'l 
1"    ■ 

.    I 


I    i 


374  THE  MECHANICAL  EQUIPMENT 

formed  principle,  so  that  the  various  edges  may  be 
ground  on  the  face  and  still  retain  their  correct  shape. 
Milling  Screw  Threads.-In  Figure  111  is  shown  a 
standard  milling  machine   set   up   to   mill   a   short 
screw  thread.    For  milling  screw  threads  special  ma- 
chines have  been  developed  which  are  also  very  use- 
ful  for  cutting  long  threads,  especially  those  that  are 
of  large  diameter.    Figure  138  shows  a  machine  of 
this  character.    The  work  is  mounted  on  the  spindles, 
as  m  an  ordinary  lathe,  but  revolves  only  for  the 
feed,  and  a  milling  cutter  is  carried  on  a  suitable 
spindle  m  the  traveling  carriage.     The  cutting  and 
feeding  motions  of  the  ordinary  lathe  are  reversed, 
as  the  cutting  motion  is  given  to  the  milling  cutter, 
which  is  in  the  head,  a,  next  the  work,  and  not  visible 
m  the  picture.    It  has  a  travel  lengthwise  correspond- 
mg  to  the  lead  of  the  screw  to  be  cut. 

The  carriage  and  head,  a,  with  the  cutter  start  at 
one  end  and  are  gradually  fed  lengthwise  while  the 
work  is  given  a  slow  rotary  feed.     The  traveling 
head  carries  a  rest,  which  takes  the  thrust  of  the 
milling  cutter.     The  spindle  that  carries  the  cutter 
has  an  adjustment  in  the  vertical  plane,  so  that  the 
cutter  may  be  tipped  to  the  angle  corresponding  with 
that  of  the  thread.    A  special  milling  cutter  is  used, 
the  teeth  of  which  are  staggered.     One  tooth  is  left 
full  for  the  purpose  of  gauging.     This  type  of  ma- 
chme  is  used  for  lead-  and  feed-screws,  worms,  spiral 
gears,  and  high  grade,  solid-end  helical  springs.    The 
quality  of  work  obtainable  by  this  method  is  very 
satisfactory,  and,  as  the  cutting  action  is  continuous, 
the  method  is  efficient  for  manufacturing  purposes. 


FIG.  138.        THREAD  MILLING  MACHINE 

Pratt  &  Whitney  Ck). 

PIG.  139.      THREAD  ROLLING  MACHINE 
E.  W.  Bliss  Co. 


375 


374  THE  MECHANICAL  EQUIPMENT 

formed  principle,  so  that  the  various  edges  may  be 
ground  on  the  face  and  still  retain  their  correct  shape 
Milling  Screw  Threads.-In  Figure  111  is  shown  a 
standard    milling   machine   set    up    to    mill    a    short 
screw  thread.    For  milling  screw  threads  special  ma- 
chines have  been  developed  which  are  also  very  use- 
ful for  cutting  long  threads,  especially  those  that  are 
of  large  duimeter.     Figui'e   138  shows  a  machine  of 
this  character.    The  work  is  mounted  on  the  spindles, 
as   m  an   ordinary   lathe,   hut   revolves   oulv   tor  the 
feed,  and  a  milling  cuttei-  is  carried   on   a  suitable 
spindle  in  the  traveling  carriage.     T]w  cutting  and 
leeding  motions  of  the  ordinaiy   lathe  are   reversed, 
as  the  cutting  motion  is  given  to  the  milling  cutter,' 
which  is  in  the  head,  a,  next  the  work,  and  not  visible 
111  the  picture.    It  has  a  travel  lengthwise  correspond- 
ing to  the  lead  of  the  screw  to  be  cut. 

The  carriage  and  head,  a,  with  the  cutter  start  at 
one  end  and  are  gradually  fed  lengthwise  while  the 
work    is   given   a   slow    rotary   feed.      The   traveling 
head  carries  a  rest,  which   takes   the  thrust   of  the 
milling  cutter.     The  spindle   that   carries   the  cutter 
has  an  adjustment  in  the  viM'tical  plane,  so  that  the 
cutter  may  be  tipped  to  the  angle  coiwTsponding  with 
that  of  the  thread.    A  special  milling  cutter  is  used, 
the  teeth  of  which  are  staggered.     One  tooth  is  left 
full  for  the  purpose  of  gauging.     This  tvpe  of  ma- 
chine is  used  for  lead-  and  feed-screws,  worms,  spiral 
gears,  and  high  grade,  solid-end  helical  spi-ings.    The 
quality  of  work  obtainable   by   this  method  is  very 
satisfactory,  and,  as  the  cutting  action  is  continuous, 
the  method  is  effieient  for  manufacturino'  purposes. 


FIG.  138.        THREAD  MILLING  MACHINE 

Pratt  &  Whitney  Co. 

FIG.  139.      THREAD  ROLLING  MACHINE 

E.   W.  Bliss  Co. 


.375 


I 


376 


THE  MECHANICAL  EQUIPMENT 


m 


Rolling   Threads.— For   certain   uses,   threads   are 
sometimes  rolled  instead  of  cut  on  solid  stock.    This 
process  can  be  employed  only  for  small  work,  such 
as  the  threading  of  bicycle  spokes.     It  has  certain 
advantages.    With  cut  threads,  the  diameter  of  the 
stock  used  has  to  be  the  outside  diameter  of  the 
thread.    With  a  rolled  thread,  it  need  be  only  about 
the  mean  diameter  of  the  thread,  since  the  material 
that  is  rolled  out  at  the  root  of  the  thread  goes  up  to 
form  the  top.    When  the  thread,  as  in  a  bicycle  spoke, 
occupies  only  a  short  length  at  the  end,  this  advan- 
tage may  mean   a   considerable   saving  of  material. 
However,  threads  formed  in  this  way  can  never  be 
theoretically  correct,   and  the  process   weakens   the 
material  so  that  a  rolled  thread  is  not  so  strong  as 
a  cut  thread  of  the  same  size. 

Figure  139  shows  a  machine  for  rolling  threads  on 
the  tops  of  cans.  Here  the  method  is  practical  and 
very  economical,  since  accuracy  in  form  is  not  re- 
quired and  the  material  is  too  thin  to  be  cut.  Sev- 
eral of  the  threaded  tops  are  shown  in  the  foreground. 
The  threading  dies,  a,  are  circular,  and  the  grooves 
that  form  the  threads  are  on  the  circumference  of  the 
roller.  The  top  is  inserted  sidewise  between  the  rolls 
and  finished  almost  instantly,  in  a  few  turns. 


CHAPTER  XXI 
GRINDING,  AND  GRINDING  MACHINERY 

Development  of  the  Grinding  Process.— The  field 
of  grinding  in  machine-shop  practice  has  been  chang- 
ing''steadily  for  the  last  forty  years.  Formerly  the 
process  was  used  only  for  sharpening  the  edges  of 
tools  that  had  been  hardened.  This  sharpening  was 
(lone  by  means  of  soft  grinding  wheels  which  were 
made  of  natural  stone,  and  which  of  necessity  ran 
at  a  comparatively  slow  speed.  About  1873,  Mr. 
F.  B.  Norton,  of  Worcester,  Mass.,  began  experiment- 
ing on  vitrified  emery  wheels;  he  put  them  on  the 
market  a  few  years  later.  Since  that  time,  other 
forms  of  abrasive  have  been  developed,  and  their 
use  has  steadily  increased.  The  first  use  was  in  con- 
nection with  rough  work  on  simple  grinding  stands, 
to  remove  sprues,  fins,  and  so  on.  From  this  phase, 
grinding  jumped  to  the  other  extreme  and  became 
an  accurate  tool-room  process.  And  now  it  is  being 
used  more  and  more  for  economical  precision  work 
on  a  manufacturing  basis.  In  the  last  of  these  uses, 
it  is  ordinarily  a  finishing  operation  on  pieces  that 
have  been  machined  with  edged  tools,  of  either  the 
lathe  or  the  milling  type. 

Special  Advantages.— Grinding  has  several  advan- 
tages possessed  by  no  other  cutting  process.     It  is 

377 


378 


THE  MECHANICAL  EQUIPMENT 


II 


If      M 


the  only  method  of  machining  steel  after  it  has  been 
hardened.     Hardening  and  tempering  almost  invar- 
iably  distort   the   pieces    treated.      When    accurate 
shapes  are  required,  as,  for  instance,  in  milling  cut- 
ters, the  pieces  are  machined  slightly  large,  to  allow 
for  this  distortion,  and  are  then  ground  accurately 
to  size  m  a  finishing  process  after  the  heat  treatment 
Another  advantage  of  the  grinding  process  is  that 
it  works  with  the  lightest  known  tool  pressure,  and 
can  be  used  on  delicate  pieces  that  would  have  a 
tendency  to  spring  away  from  the  cutting  edge  of  an 
ordinary  tool.    This  advantage  is  of  particular  value 
m  the  grinding  of  long  spindles,  shafts,  and  so  on. 
btill  another  advantage  is  that  the  scale  on  cast- 
ings and  forgings,  which  destroys  the  cutting  edge 
of  an  ordinary  tool,  does  not  interfere  with  grinding 
and,  whereas  one-eighth  inch  is  the  usual  allowance 
tor  finish   with  an   edged   tool,   one  sixty-fourth   or 
one  thirty-second  of  an  inch,  only,  need  be  allowed 
tor  grinding— just  enough  to  insure  that  the  surface 
will   be  properly  cleaned   up.     A   disadvantage  for 
accurate  sliding  surfaces  in  machine  tools  is  the  fac! 
that  such  surfaces,  when  ground,  may  retain  some 
ot  the  emery  and  therefore  cut  each  other.    For  this 
reason,  grinding  is  not  used  in  certain  places  where 
otherwise  it  would  be  of  great  advantage. 

Grinding  Abrasives.— Modern  abrasives  are  of  two 
kinds,  natural  and  artificial.  The  natural  abrasives 
are  emery  and  corundum.  Emery  is  a  mineral,  and  a 
mixture  of  aluminum  oxide  and  iron  oxide  in  a  ratio 
of  about  60  per  cent  to  40  per  cent.  Corundum  is  a 
purified  form  of  emery,  with  from  80  to  85  per  cent 


GRINDING,  AND  GRINDING  MACHINERY      379 

of  aluminum  oxide.  The  iron  oxide  present  in  these 
two  materials  is  undesirable,  and  has  no  abrasive 
quality.  Because  of  this,  emery  in  particular  is  little 
used  on  automatic  grinding  machines  at  the  present 
time.  . 

The  artificial  abrasives  are  the  following:  car- 
borundum, which  is  carbide  of  silicon  made  in  the 
electric  furnace  from  coke  and  sand,  with  salt  and 
sawdust  added  to  facilitate  the  reducing  process; 
alundum,  which  is  the  trade  name  for  a  material 
consisting  chiefly  of  oxide  of  aluminum,  made  from 
bauxite,  a  clay  mined  in  Arkansas,  and  similar  in 
chemical  composition  to  the  ruby  and  the  sapphire; 
and  crystolon,  which  is  carbide  of  silicon,  and  which, 
like  carborundum,  is  made  from  coke,  sand,  sawdust, 
and  salt.  Unlike  alundum,  crystolon  has  no  counter- 
part in  nature.  It  is  most  efficient  when  used  on 
materials  of  low  tensile  strength,  such  as  cast  iron, 
brass,  bronze,  and  aluminum.  Aloxite,  carbolite,  and 
carbondite  are  recent  materials,  and  are  compounds  of 
aluminum  or  silicon.  All  the  artificial  abrasives  are 
made  by  fusing  the  raw  materials  at  high  temperatures 
in  an  electric  furnace. 

The  natural  abrasives  are  tougher  than  the  artifi- 
cial, but  not  nearly  so  hard.  The  shape  and  form  of 
fracture  of  the  abrasive  particles  are  of  importance, 
as  well  as  their  hardness.  The  diamond  is  the  hardest 
substance  known,  but  a  grinding  wheel  made  up  of 
smooth,  round  diamonds  would  be  of  little  use  for 
cutting  purposes.  One  of  the  great  advantages  of 
the  artificial  abrasives  is  that  they  break  with  a 
clean  crystalline  fracture  which  gives  the  particles 


380 


THE  MECHANICAL  EQUIPMENT 


m 


sharp  cutting  edges.  When  the  steel  dust  produced 
by  these  wheels  is  examined  under  a  microscope,  it 
IS  found  to  consist  of  small,  curled  chips,  which  are 
similar  to  the  large  ones  produced  by  an  ordinary 
.  steel  cutting  tool. 

Grinding  Wheels.~A  grinding  wheel  is  practically 
a  milling  cutter  with  an  infinite  number  of  very  small 
cutting  edges.  The  abrasive  used  in  grinding  wheels 
IS  ground,  screened  through  sieves,  and  graded  ac- 
cording to  the  number  of  the  finest  meshed  screen 
through  which  it  will  pass.  For  instance,  a  36-grain 
wheel  contains  abrasive  which  passes  through  a  36- 
mesh  screen.  6     a  ou 

The   bond,   or  adhesive  substance   that   binds   the 
abrasive  together,  is  usually  composed  of  clay,  silicate 
of  soda,  or  shellac.    Kubber,  celluloid,  or  an  oxidiz- 
ing oil  are  also  employed  in  some  instances.     Four 
types  of  bonded  wheels  are  used,  known  as  vitrified, 
silicate,  elastic,  or  vulcanite-according  to  the  process 
of  their  manufacture  and   the  nature   of  the   bond 
used-and  finally,  disc  wheels.     In   vitrified  wheels 
the  bond  IS  a  mineral  and  clay  mixture  fused  into  a 
porcelain.    These  wheels  are  the  most  commonly  used 
today   as  they  are  not  affected  by  heat,  cold,  water, 
oils,  or  acids.    They  are  porous,  and  free  from  hard 
and    soft    spots.     Their   porous    texture    allows    the 
particles  of  abrasives  to  be  torn  out  readily  in  the 
grinding  process,  and  the  wheel  does  not  clog  up  so 
easily  with  the  material  being  worked  upon.    On  the 
other  hand,  a  vitrified  wheel  is  not  so  strong  as  an 
elastic    wheel    and    is    more    easily    broken.     Cons(«- 
quently  the  vitrified  process  cannot  be  used  for  thin 


GRINDING,  AND  GRINDING  MACHINERY      381 

wheels,  and  it  is  not  advisable  to  attempt  very  heavy 
side  cuts  with  them.  •  : 

Silicate  wheels  derive  their  name  from  the  silicate 
of  soda  which  constitutes  the  bond.  These  are  known 
also  as  semi-vitrified  wheels.  They  cut  smoothly 
and  with  little  heat;  and  they  are  lised  for  grinding 
tools,  when  the  temper  must  not  be  .drawn.  Their 
grade  is  dependable  for  the  process  of  manufacture 
and  can  be  easily  controlled;  they  may  be  made  in 
large  sizes.  Vitrified  wheels  are  rarely  made  above 
36  inches  in  diameter,  while  silicate  wheels  can  be 
obtained  up  to  60  inches.  In  elastic  wheels,  shellac 
forms  the  bond,  and  in  vulcanite  wheels,  rubber.  The 
elastic  wheels  are  strong,  and  consequently  very  thin 
wheels  may  be  made  which  are  not  only  elastic  but 
which  have  smooth-cutting  qualities;  they  can  be 
used  for  deep  sid«  cuts.  The  disc  wheel  is  wholly 
different;  it  consists  of  an  accurately  balanced  steel 
disc  on  which  is  cemented  a  cloth  or  paper  impreg- 
nated with  powdered  abrasive  of  the  grain  or  fine- 
ness required. 

Grading.— The  nature  of  the  bond  of  the  grinding 
wheel  determines  how  strongly  the  particles  of 
abrasives  will  be  held  together— a  question  of  great 
importance  in  grinding  practice.  Wheels  from  which 
the  abrasive  is  readily  torn  are  known  as  soft-grade 
wheels,  and  those  which  retain  the  grit  strongly  are 
called  hard-grade  wheels.  The  word  ** grain"  in 
connection  with  grinding  wheels  refers  to  the  size 
of  the -particles  of  abrasive;  the  word  *^ grade''  refers 
to  the  hardness  or  softness  of  the  bond.  The  former 
is  given  in  numbers  and  the  latter  usually  by  letter 


I 


ii 


■ ' 


111* 


; 


\'U 


382 


THE  MECHANICAL  EQUIPMENT 


I'         !| 


for  vitrified  and  silicate  wheels.     For  the  grades  of 
elastic  wheels,  numbers  are  usually  used. 

Selection  of  Wheels.— The  following  elements  must 
be  considered  in  selecting  the  proper  grinding  wheel 
for  any  given  work:  material  to  be  ground,  degree 
of  accuracy  required,  quality  of  finish  required,  size 
and  shape  of  the  work,  whether  it  is  to  be  ground 
wet  or  dry,  whether  the  work  calls  for  external,  in- 
ternal,  or  surface  grinding,  and   the   speed   of  the 
work,  the  rapidity  of  the  side  traverse  speed,  and  the 
depth  of  the  cut.  It  is  apparent,  then,  that  no  specific 
rules  can  be  given  in  regard  to  the  selection  of  grind- 
ing  wheels.      In   general,    corundum    and    alundum 
wheels  are  most  efficient  for  hard  and  soft  steel,  and 
carborundum  and  crystolon  for  cast  and  chilled  iron. 
Soft  bonded  wheels  are  generally  used  for  very  hard 
materials,  and  hard  bonded  wheels  for  medium  and 
soft  materials.     It  is  best  to  use  a  medium-grade 
wheel  for  grinding  brass  or  bronze.    One  of  the  fac- 
tors that  must  be  taken  into  consideration  when  a 
wheel  is  selected,  is  the  arc  of  contact  between  the 
work  and  the  grinding  wheel.    Harder  bonded  wheels 
must  be  used  for  grinding  small  diameters  than  for 
grinding  large  ones,  and  soft  wheels  are  the  best  for 
surface  grinding. 

The  harder  grades  of  corundum  and  alundum 
wheels  may  be  run  at  speeds  from  5000  to  7000  feet 
surface-speed  per  minute;  the  softer  grades  should 
not  be  run  at  a  rate  exceeding  5000  feet.  Carbor- 
undum and  crystolon  wheels  should  be  run  a  little 
more  slowly.  For  cylindrical  grinding,  wheels  should 
usually  be  run  from  5000  to  7000  feet  per  minute; 


GRINDING,  AND  GRINDING  MACHINERY      383 

for  surface  grinding,  about  5000  feet  per  minute,  and 
for  cutter  grinding,  from  4000  to  5000  feet  per 
minute. 

Since  the  proper  selection  of  grinding  wheels  is 
closely  related  to  their  efficiency,  it  is  desirable  that 
the  choice  of  grade  and  grain  and  of  the  various 
speeds  and  feeds  should  be  referred  to  the  makers 
of  the  wheels,  wherever  there  is  much  grinding  to  be 
done.  As  grinding  is  a  specialized  field,  these  firms 
have  experts  whose  entire  time  is  given  to  advising 
customers  as  to  just  what  will  best  suit  their  needs, 
and  naturallv  such  help  is  of  the  verv  greatest  value. 

Mounting  of  Wheels.— In  view  of  the  high  speeds, 
just  mentioned,  it  is  obvious  that  the  wheels  should 
be  absolutely  steady  in  order  that  there  be  no  ex- 
cessive vibration,  with  its  accompanving  danger.  As 
therp  is  always  the  possibility  that  bonded  wheels 
mav  become  ruptured,  however  well  mounted  they 
may  be,  the  operator  should  be  protected,  whenever 
possible,  by  a  hood  like  that  shown  at  a.  Figure  141. 
This  is  made  in  such  a  wav  that  if  the  wheel  should 
break,  the  operator  would  be  practically  secure 
against  injure-.  Wheels  should  be  mounted,  as  shown 
in  Figrure  140,  between  two  safety  flanges,  which 
preferably  should  not  be  less  than  one-half  or  one- 
third  the  diameter  of  the  wheel.  These  flanges 
should  bear  on  the  wheel  onlv  at  their  outer  edg:e, 
and  a  comnressible  washer  of  rubber  or  blotting 
paper  should  be  interposed  between  them  and  the 
wheel. 

A  wheel  so  mounted  is  held  near  the  rim:  conse- 
quentlv  the  centrifugal  strains  are  much  less  than 


. 


^. 


384 


i 


I 


I 


I 


THE  MECHANICAL  EQUIPMENT 


.  •  T/7/S  Flange  ffey^c/  o r  Pressed 


Leo  a  Bushing 


Con^pressible  Washer  of 
.-•'Rubber  or  B/offing  Paper 


^Central  PorHon  of  Flange 
re/eiyec/  f-o  git^e  bearing  surface 
Only  near  P/m. 


FIG.    140.      CORRECT  MOUNTING  FOR  A  GRINDING  WHEEL 

they  would  otherwise  be.  When  the  wheel  wears 
down  toward  the  edge  of  the  flanges,  a  smaller  pair 
may  be  used.  Many  grinding  wheels  have  straight 
sides,  but  those  with  sloping  sides  are  naturally  some- 
what stronger  against  bursting,  since  the  flanges  have 
a  better  hold.  Even  when  there  are  safety  flanges, 
protection  hoods  should  be  used.  The  laws  of  most 
states  require  the  removal  of  the  dust— which  is  a 
menace  to  the  health  of  the  workman— by  means  of 
some  exhaust  system.  In  such  instances  a  hood  is 
required  anyway,  and  it  can  easily  be  made  strong 
enough  to  furnish  complete  protection.  The  working 
speeds,  as  given  by  the  good  makers,  allow  a  factor 
of  safety  of  from  6  to  12,  and  all  wheels  over  five 
inches  in  diameter  are  tested  at  a  speed  nearly  twice 
that  for  which  they  are  recommended. 


FIG.   141.      NORTON  GRINDING  WHEEL  STAND 

FIG.   142.      GARDNER  HORIZONTAL  DISC  AND  RING  GRINDER 

385 


f  ^ 


384 


TirK  MECHANICAL  EQCIPMENT 


'iv      ' 


«C3% 


Leod  Bushinq 


Cornpressible  Washer  of 
■  ■'  Rubber  or  B/o/fmr^  Paper 

yThis  Ffange  Keyec/ or  Prf^sec/ 
T/(^ht  on  SpincJJe 


m 


m 


^  Centra  I  Porfion  of  Flange 
re/ei\^ej/  /o  gi>^e  bearing  surface 
Only  near  Rim. 


FIG.    140.       CORRECT    MOTJXTINd    FOR   A    (JRIXDIXiJ    WHEEL 

they  would  otlierwiso  be.  W'Ikmi  tlio  wlieel  wciu-^ 
down  toward  tlie  edge  of  tlie  llaiioes,  a  smaller  pair 
may  be  used.  Many  grinding  wlieels  liave  straight 
sides,  but  those  with  sh)ping  sich's  are  naturally  some 
what  stronger  against  l)ursting,  since  the  flanges  have 
a  better  hold.  Ev<'n  when  there  are  safetv  llanues, 
protection  hoods  should  be  used.  The  laws  oi*  most 
states  require  the  removal  ol'  the  dust— which  is  a 
Tuenace  to  the  health  of  the  woikman— bv  means  ot 
some  exhaust  system.  In  such  instances  a  hood  is 
required  anyway,  and  it  can  easily  be  made  stroiii; 
enough  to  furnish  com|)lete  protection.  The  workini! 
speeds,  as  given  by  the  good  makers,  allow  a  factor 
of  safety  of  from  (i  to  12,  and  all  wheels  over  tive 
inches  in  diameter  are  tested  at  a  speed  nearly  twic 
that  for  which   thev  are   recommended. 


FIG.    141.      NORTOX   r.RIXOlXC.   WHEEE  STAXO 

FIG.  142.     GAnnNKR  noiMZoxTAT-  DISC  AXi)  Rixc.  «;inNm:R 

3S5 


K 


I*' 


386 


THE  MECHANICAL  EQUIPMENT 


Types  of  Grinding  Machines.— The  simplest  type  of 
grinding  machine  is  a  plain  emery-wheel  stand,  one 
of  which  is  shown  in  Figure  141.  These  may  mount 
one  or  two  wheels.  The  commonest  way  of  using 
a  wheel  is  shown  on  the  right.  The  wheel  is  used 
on  the  outer  surface,  and  the  work,  which  is  pressed 
up  against  it  by  hand,  is  supported  by  the  adjustable 
rest,  b,  which  is  set  up  as  close  to  the  wheel  as  pos- 
sible without  bringing  it  into  contact.  When  wet 
grinding  is  done,  the  pan,  c,  is  made  to  catch  the 
water.  Another  way  to  arrange  a  wheel  is  to  have 
the  top  of  it  project  slightly  up  through  an  opening, 
d,  m  a  surface  plate,  e.  Then  if  the  work  is  passed 
'backward  and  forward  over  the  wheel,  an  approx- 
imately flat  surface  can  be  obtained. 

Another  and  much  more  accurate  way  of  obtain- 
ing a  flat  surface  is  to  use  the  side  of  the  wheel,  as 
shown  in  Figure  142.     In  this  case,  also,  there  is  a 
double-ended   stand   with   a   horizontal,   ball-bearing 
spindle  that  has  on  the  right  a  vitrified  ring  wheel, 
which  grinds  on  the  face,  a.    The  work  is  supported 
on  the  table,  b,  either  directly  or  by  a  suitable  fix- 
ture.    The  table  and  the  carriage,  c,  may  be  swung 
backward  and  forward  across  the  face  of  the  wheel 
on  the  rocker  shaft,  d.    The  table  may  be  set  square, 
as  shown,  or  tilted  on  an  angle  and  locked  in  that 
position  by  the  bolt,  e;  it  may  also  be  raised  and 
lowered.    The  work  is  pressed  up  against  the  wheel 
by  the  handle,  f,  and  the  amount  of  forward  motion 
may  be  controlled  by  the  micrometer  stop,  g.     On 
the  other  end  of  the  machine  is  a  disc  wheel,  h.    This 
wheel,  which  is  of  steel,  has  an  abrasive  cloth   or 


GRINDING,  AND  GRINDING  MACHINERY      387 

paper  mounted  on  its  face.  Very  large  wheels  of 
this  type  are  made  which  run  in  a  horizontal  plane. 
The  pieces  to  be  ground  are  placed  on  top  of  the 
wheel,  but  they  are  kept  from  rotating  with  it.  Their 
own  weight  furnishes  the  necessary  pressure.  There 
is  no  danger  that  the  disc  wheel  will  burst.  This 
wheel  is  being  widely  used  for  many  kinds  of  sur- 
face grinding. 

For  still  more  accurate  surface  grinding,  machines 
of  the  types  shown  in  Figures  143  and  144  are  used. 
The  vertical  grinder,  Figure  143,  uses  the  face,  a,  of 
a  cup-shaped  wheel.  This  type  of  machine  is  both 
accurate  and  very  efficient  for  work  on  large  flat 
surfaces;  it  is  made  in  sizes  large  enough  to  grind 
faces  25  inches  wide  and  6  feet  long,  or  circular  ones 
30  inches  in  diameter.  Such  a  machine  will  finish 
many  kinds  of  work  formerly  done  on  the  planer  or 
milling  machine  with  greater  accuracy  and  at  less 
cost.  The  ring  wheel  is  clamped  to  a  circular  flange 
at  the  lower  end  of  a  vertical  spindle.  It  is  rein- 
forced against  bursting  by  an  adjustable  steel  band, 
which  may  be  set  up  as  the  wheel  wears. 

The  wheel  spindle  is  carried  in  an  adjustable 
counterbalanced  head,  b,  which  has  a  sensitive  ver- 
tical feed  operated  either  by  hand  or  automatically. 
Provision  is  made  for  automatically  disengaging  the 
feed  when  the  proper  depth  of  cut  has  been  reached. 
A  pump  supplies  an  abundance  of  water,  which  is 
delivered  through  the  spindle;  the  centrifugal  force 
drives  the  water  out  between  the  wheel  and  the  work, 
keeping  both  cool  and  free  from  dust.  A  stream  is 
also  provided  outside  the  wheel  for  cleansing  pur- 


II 


FIGS.  143  AND  144.      SURFACE  GRINDERS 
The  vertical  grinder  in  the  upper  view  is  built  hv  Pr«ff  a.  xnrhi^^r, 
Co.    The  horizontal  grinder  be^L  is  buiirbyTlle  Norton"  rlnZrcJ^ 

388 


GRINDING,  AND  GRINDING  MACHINERY      389 

poses.  The  table  is  provided  with  a  high  water 
guard,  c,  which  catches  the  water  and  returns  it  to 
the  supply  tank. 

Various  forms  of  chucks  are  used  to  hold  the  work. 
These  may  be  circular  with  an  automatic  rotary  feed, 
in  which  case  the  table  is  partly  under  the  wheel,  as 
shown  in  the  illustration.  This  arrangement  permits 
of  setting  the  work  on  the  exposed  portion  of  the 
table  while  the  grinding  operation  is  going  on;  thus 
the  action  of  the  machine  is  continuous.  For  plain 
flat  pieces,  especially  when  they  are  thin,  as  in  the 
case  of  saw  blades,  magnetic  chucks  are  used  to 
great  advantage.  When  rotary  chucks  are  used, 
the  table  remains  stationary,  and  the  only  feed  i.s 
rotary;  for  long  work,  the  table  may  be  given  a  trans- 
verse feed  motion  along  the  bed.  The  length  of 
travel  is  governed  by  means  of  suitable  dogs,  d,  at 
the  front  of  the  table,  which  act  like  those  described 
in  connection  with  the  planer.  Figure  86.  In  this 
machine,  as  in  other  types  of  grinding  machines,  the 
table  is  provided  with  extensions,  e;  these  protect 
the  ways  from  water  carrying  abrasive  dust,  which 
would  tend  to  wear  them  away. 

In  the  open-side  surface  grinder,  shown  in  Figure 
144,  the  grinding  is  done  on  the  edge  of  the  wheel 
instead  of  on  the  face.  This  machine  can  therefore 
be  used  for  finishing  grooves,  irregular  shapes,  and 
surfaces  that  have  projections.  The  work  is  carried 
on  a  slotted  surface  on  the  table,  which  is  between 
the  sides  of  the  water  guard  and  does  not  show  in  the 
photograph.  This  surface  is  15  inches  wide,  and 
from  6  to  14  feet  long  according  to  the  length  of 


FIGS.   143  AND  144.      SURFACE  GRINDFRS 
The  vmical  jrri.Mler  in  the  upper  v.Vw  is  J.nilr  hv  Prntt  &  WhitnPV 
Co.    Uhe  horizontal  ^^-inder  hHow  is  huilt  l,v  the  Norton  (^Hn'linrCV 


;;ss 


GRINDING,  AND  GKINDINC;  MACIIINKKY      389 

poses.  Tlic  ta])l('  is  provided  witli  a  lii^b  water 
o-uard,  (',  wliicli  calclK^s  llic  watei-  and  returns  it  to 
the  supply  tank. 

Various  forms  of  eliueks  are  used  to  hold  the  work. 
'Piiese  nuiy  Ix^  cireulai"  with  an  autoinatie  rotary  feed, 
in  whieh  ease  the  table  is  ])artly  under  the  wheel,  as 
shown  in  the  illustration.  This  arran.i»enient  permits 
of  setting  the  work  on  the  exposed  portion  of  the 
table  while  the  grinding  operation  is  going  on;  thus 
the  action  of  the  maehine  is  eontinuous.  For  plain 
Hat  pieees,  especially  when  they  are  thin,  as  in  the 
ease  of  saw  blades,  nuignetie  ehueks  are  used  to 
great  advantage.  AVlien  rotary  ehueks  are  used, 
the  table  remains  stationary,  and  the  only  tecnl  is 
rotary;  for  long  work,  the  table  may  i)e  given  a  trans- 
verse feed  motion  along  the  bed.  The  length  of 
travel  is  governed  by  means  of  suital)le  dogs,  d,  at 
tlie  front  of  the  table,  whieh  aet  like  those  described 
in  connection  with  the  i)laner,  Figure  86.  In  this 
machine,  as  in  other  types  of  grinding  machines,  the 
table  is  provided  with  extensions,  e;  these  protect 
the  ways  from  water  carrying  abrasive  dust,  which 
would  tend  to  wear  them  away. 

in  the  open-side  surface  grinder,  shown  in  Figure 
144,  the  grinding  is  done  on  the  iHhj;('  of  the  wheel 
instead  of  on  the  face.  This  machine  can  therefore 
be  used  for  tinishing  grooves,  irregular  shapes,  and 
surfaces  that  have  projections.  The  work  is  carried 
on  a  slotted  surface  on  the  table,  which  is  between 
the  sides  of  the  water  guard  and  does  not  show  in  the 
photograph.  This  sui"face  is  15  inches  wide,  and 
from  ()   to    14   feet   long   according   to   the   length   of 


II 


J 


I 


I 


i^ 


i* ' 


390 


THE  MECHANICAL  EQUIPMENT 


the  machine.  The  wheel  head  mounted  on  the  up- 
right carries  a  wheel  14  inches  in  diameter,  which 
can  be  raised  to  give  a  clear  distance  of  17  inches 
to  the  surface  of  the  table;  when  it  is  raised,  a  mag- 
netic chuck  can  be  used  on  a  supplementary  table. 
The  work  has  a  horizontal  traverse  under  the  wheel, 
and  there  are  accurate  adjustments  for  controlling  the 
depth  of  cut.  The  travel  of  the  table  is  controlled  by 
adjustable  dogs,  as  in  the  machine  just  described. 

Figure  145  shows  a  plain  cylindrical  grinding  ma- 
chine used  for  producing  cylindrical  and  conical  sur- 
faces.    This  type  is  used  for  finishing  surfaces  that 
have  been  roughed  off  in  a  lathe  to  within  1/64  or 
1/32  of  an  inch  of  the  required  size.  .In  addition  to 
the  rapid  rotation  of  the  grinding  wheel,  these  ma- 
chines have  the  following  motions:  a  slower  rotation 
of  the  work,  as  in  a  lathe,  of  from  25  to  75  feet  per 
minute;  a  traverse  of  either  the  wheel  or  the  work 
longitudinally  of  from  one-fourth  to  three-fourths  the 
width  of  the  emery-wheel  face  for  each   revolution 
of  the  work;  a  cross  feed  or  adjustment  for  setting 
the  wheel  to  give  the  proper  diameter  of  work.    Most 
machines  have  also  a  horizontal  swiveling  adjustment 
that  can  be  used  in  the  grinding  of  tapers. 

The  feeds  that  govern  the  depth  of  cut  have  a 
range  from  .00025  inch  to  .004  inch  with  each  re- 
versal of  the  table,  and  are  automatically  thrown  out 
when  the  work  is  down  to  size.  The  wheel  spindle 
is  of  chrome-nickel  steel,  hardened,  ground  and 
lapped,  and  is  capable  of  carrying  a  wheel  20  inches 
in  diameter  and  3  inches  thick.  The  speeds  of  the 
wheel,  the  work,  and  the  feed  of  the  table  are  en- 


FIGS.  145  AND  146.      GRINDING  MACHINES 

The  plain  cvlindrical  grinder  above  is  built  by  the  Norton  Grinding 

Co.  The  universal  j?rinder  below  is  bnilt  by  Brown  &  Sharpe  Mfg.  Co, 

391 


390 


THE  ME(  HANICAL  EQUIPMENT 


the  machine.  The  wheel  head  mounted  on  the  up- 
right carries  a  wheel  14  inches  in  diameter,  which 
can  be  raised  to  give  a  clear  distance  of  17  inches 
to  the  surface  of  the  table;  wlien  it  is  raised,  a  mag- 
netic chuck  can  be  used  on  a  supplementary  ta])lc. 
The  woi-k  has  a  horizontal  traverse  under  the  wheel, 
and  there  are  accurate  adjustments  for  controlling  the 
depth  of  cut.  The  travel  of  the  table  is  controlled  by 
adjustable  dogs,  as  in  the  machine  just  described. 

Figure  U.!  shows  a  plain  cylindrical  grinding  ma- 
chine used  for  producing  cylindrical  and  conical  sur- 
faces.    This  type  is  used   for  finishing  surfaces  that 
have  been  roughed  oflP  in  a  lathe  to  within   l/()4  or 
1/32  of  an  inch  of  the  re(|uired  size,     in  acklition  to 
the  raj)id  rotation  of  the  grinding  wheel,  these  ma- 
chines have  the  following  motions:  a  slower  rotation 
of  the  work,  as  in  a  lathe,  of  from  '2^)  to  '.'»  feet  per 
minute;  a   traverse  of  either   the   wheel   or   the   work 
longitudinally  of  from  one-fourth  to  three-fourths  the 
width    of   the   emery-wheel    face    for   each    revolution 
of  the  work:  a  cross  feed  or  adjustment  for  setting 
the  wheel  to  give  the  pro|)er  diameter  of  work.     Most 
machines  have  also  a  horizontal  swiveling  adjustment 
that  can  be  usinl  in  the  grinding  of  tapers. 

The  \'vv(y  that  govern  the  depth  of  eut  have  a 
range  from  .()()()2:)  inch  to  .004  inch  with  each  re- 
versal of  the  table,  and  are  automatically  thrown  out 
when  tlie  work  is  down  to  size.  The  wheel  spindle 
is  of  chrome-nickel  steel,  hardened,  ground  and 
lapped,  and  is  capable  of  carrying  a  wheel  20  inche> 
in  diameter  ami  :{  inehes  thiek.  The  speeds  of  tin- 
wheel,    the    work,   ;ni(l    the    {'vOi\    of   \hr    table   are   en 


.viSMfSy 


FIGS.   145  AND  146.      GRINDING  MACHINES 
Tilt'  ithiiii  cvIiiKn-ii'jH  Ln'iii<1<M-  mIh.vo  is  huili    l>y  ilu'  Norion  (Iriiidinj: 
Co.   Tlic  mii"vt'rs:il  irrindrr  hclow  i<  l.iiili  l.y  I'mwii  ,K:  Sliiir]..'  .Mlu.  < '<», 

:i'.ti 


Mfpi 


392  THE  MECHANICAL  EQUIPMENT 

tirely  independent  of  one  another;  the  wheel  speed 
varies  from  1360  to  1630  r.p.m.,  the  work  speed  from 
27  to  207  r.p.m.,  and  the  feed  of  the  table  from  21 
inches  to  126  inches  a  minute.  Three  steady-rests 
are  provided  for  supporting  slender  work,  and  pro- 
vision is  made  for  an  abundant  supply  of  water— 
the  tank  and  pump  are  located  inside  the  bed  of  the 
machine.  In  this  machine,  as  in  all  other  high-grade 
grinding  machines,  all  the  working  surfaces  are  pro- 
tected from  grit-bearing  water,  which  would  soon 
destroy  their  accuracy.  All  changes  are  effected  from 
the  front  of  the  machine. 

Figure  146  shows  a  universal  grinding  machine  that 
has  a  wider  range  of  work.    The  wheel  stand  in  this 
type  of  machine  has  a  horizontal  swiveling  adjustment, 
a,  so  that  the  wheel  can  be  set  in  any  position  without 
interference.     The  upper  portion,  b,  of  the  table  has 
a  swiveling  motion  about  a  central  stud  in  the  lower 
part,  c,  and  the  headstock  also  swivels,  at  d.     By 
means  of  these  adjustments,  any  taper  to  be  ground 
may  be  handled  accurately.  In  addition  to  the  swivel- 
ing adjustment,  the  wheel  stand  has  a  hand-operated 
transverse  adjustment  that  can  be  set  to  thousandths 
of  an   inch,   and   an   automatic   cross  feed   of   from 
.00025  to  .004  inch,  which  operates  at  each  reversal 
of  the  table  and  throws  out  when  the  work  is  to 
size.     In  Figure  146  the  steady-rests  and  the  other 
equipment  necessary  are  shown  on  the  floor.    An  in- 
ternal grinding  fixture,  f,  consists  of  a  separate  head 
with  an  independently  driven  spindle,  on  the  end  of 
which  a  small  wheel  may  be  mounted  for  grinding 
out  small  holes  and  cylinders. 


GRINDING,  AND  GRINDING  MACHINERY      393 

Figures  147  and  148  show  two  machines  designed 
especially  for  internal  grinding.  The  Bryant  grinder, 
shown  in  Figure  147,  has  a  chuck,  a,  in  which  is 
mounted  the  piece  to  be  ground,  b.  This  chuck,  with 
the  work,  is  given  an  independent  rotation  by  the 
pulley,  c,  in  the  fixed  head  of  the  machine,  and  the 
grinding  wheel,  d,  is  carried  on  the  end  of  a  shaft 
mounted  in  the  head,  or  box,  e,  which  depends  from 
the  heavy  bar,  f.  A  belt,  not  shown,  drives  the 
grinding  spindle  from  a  pulley,  which  is  inside  the 
box,  e.  For  the  longitudinal  motion  of  the  grinding 
wheel  a  traverse  is  given  to  the  bar,  f,  by  the  mech- 
anism at  the  right,  operated  either  automatically  or 
by  hand.  An  arm  projects  downward  from  the 
swinging  box,  e,  and  by  bearing  against  a  former,  or 
control-plate,  inside  the  frame,  controls  the  forward 
and  backward  position  of  the  wheel,  as  well  as  the 
diameter  being  ground. 

The  control-plate  against  which  the  arm  bears  may 
be  straight  and  set  parallel  with  the  axis  for  cylinder 
grinding,  or  on  a  taper  for  taper  grinding,  and  its 
position  may  be  adjusted  by  a  feed  screw  under  con- 
trol of  the  mechanism,  g,  at  the  front  of  the  machine. 
The  control-plate  need  not  necessarily  be  straight 
and  by  giving  it  a  curved  contour  irregular  shaped 
holes  may  be  ground.  By  turning  the  feed  screw  the 
control-plate  inside  may  be  moved  in  and  out  for 
varying  the  depth  of  cut.  A  stop-pin,  h,  prevents 
the  wheel  from  swinging  forward  far  enough  to  strike 
the  opposite  side  of  the  hole. 

In  the  machine  shown  in  Figure  148,  the  work  is 
mounted  on  a  table  that  carries  the  work  across  the 


if 


il 


I 


i 


TIG.   147.      BRYANT  CHUCKING  GRINDER 
MG.    148.      HEALD  INTERNAL  GRIXDINiJ    MACHINE 


3i)4 


GRINDING,  AND  GRINDING  MACHINERY      395 

wheel  with  an  automatic  transverse  movement  to  and 
fro.  The  wheel  is  mounted  on  the  end  of  a  spindle, 
a,  which  is  driven  from  the  small  pulley  at  the  ex- 
treme left.  This  spindle  is  adjustable  eccentrically 
in  a  larger  one,  b,  which  rotates  about  a  fixed  axis 
in  the  main  bearings,  c,  of  the  head.  The  outer 
spindle,  b,  has  a  slow  rotation  that  carries  the  axis 
of  the  spindle,  a,  around  in  a  circle,  the  diameter  of 
which  is  determined  by  the  amount  of  eccentricity 
between  the  two  axes.  The  grinding  wheel  there- 
fore has  two  motions:  a  rapid  rotation  about  the  axis 
of  its  own  spindle,  a,  which  gives  the  cutting  speed; 
and  a  slower  one  about  the  axis  of  the  spindle,  b, 
which  gives  a  circumferential  motion  of  the  wheel 
as  a  whole  around  the  inside  surface  of  the  work. 
The  degree  of  eccentricity  can  be  varied,  by  means 
of  an  adjustment  at  d,  to  suit  the  amount  of  travel 
that  it  is  necessary  to  give  the  wheel.  The  depth  of 
cut  is  controlled  by  the  micrometer  screw,  e. 

This  form  of  internal  grinder  is  useful  for  finishing 
the  bores  of  automobile  cylinders  and  other  parts 
that  cannot  be  convenientlv  mounted  for  rotation. 
When  the  work  can  be  easily  turned,  it  can  be 
mounted  in  a  chuck  on  the  head  of  the  machine,  and 
the  wheel  can  be  mounted  at  the  end  of  a  spindle 
carried  by  the  sliding  table.  The  work  spindle  and 
the  wheel  spindles  are  given  independent  rotations 
by  means  of  separate  belts,  and  the  depth  of  cut  is 
controlled  by  an  adjusting  screw  on  the  side  of  the 
table,  as  shown  in  Figure  148. 

Tool  Grinders. — Grind  stones  are  used  only  for 
thin-edged  tools,  such  as  cutlery  and  wood-working 


TIC.    147.       BRVAXT   CUVCKlSr.   r.RlSUKK 

fk;.    14S.     Ml  \[j,  ixTKKNM.  .;mxnix<,  aiachixh 


:i:'i 


w 


(JRIXDING,  AM)  (;RIM)1N(J   MACHINERY      :J05 

..lu'c'l  Willi  an  autoinatic  Iraiisvt'isc  inovcnu'iit  to  ami 
fro.  The  wIkh'I  is  moiniliMl  on  tlir  end  of  a  spindle, 
.,,  wliich  is  (IriviMi  from  tin'  sinall  pullry  at  tlii»  ox- 
livinc  left.  This  sj)in(ll('  is  adjustahlc  (M-ccntrically 
ill  a  lar^ci-  one,  1),  wliicli  I'otatcs  ahont  a  lixcd  axis 
in  the  main  hcarini-s,  c,  of  the  head.  Tin'  outer 
spindle,  I),  lias  a  slow  rotation  that  carries  the  axis 
of  the  spindle,  a,  aronn<l  in  a  circle,  the  diameter  of 
which  is  detei-mined  by  tln^  amount  of  eccentricity 
h<*tw(H^u  the  two  axes.  The  .t»i-indin,i'-  wheel  there- 
fore has  two  motions:  a  rapid  rotation  about  the  axis 
of  its  own  spin<lle,  a,  which  liivcs  the  cutting-  speed; 
and  a  slower  one  ahont  tin*  axis  of  the  spindle,  h, 
which  uivcs  a  cii-cumferential  motion  of  the  wheel 
as  a  whole  around  the  inside  sui'face  of  the  work. 
The  dcm*cc  of  eccentricitv  can  he  vai'ied,  hv  nu^aus 
of  an  adjustment  at  d,  to  suit  the  amount  of  travel 
that  it  is  necessary  to  i;ive  the  wheel.  The  depth  of 
cut   is  controlled   hv  the  mici-ometei"  sci'ew,  e. 

This  form  of  internal  .grinder  is  useful  for  finishin<; 
the  hores  of  automobile  cylindei-s  and  otluM*  parts 
that  cannot  be  conveniently  moulded  foi*  rotation. 
When  the  work  can  be  easily  tui'ne(l,  it  can  be 
nionnted  in  a  chuck  on  the  head  of  the  machine,  and 
the  wheel  can  be  moulded  at  th.e  end  of  a  spindle 
carried  by  the  slidin.n'  table.  The  work  spindle  and 
the  wheel  spindles  are  liiven  independent  i-otations 
by  ni(»ans  of  separate  belts,  and  the  depth  of  cut  is 
«'ont rolled  bv  an  adiustini;-  screw  on  the  side  of  the 
table,  as  shown  in  Fi.i;ure  14S. 

Tool  Grinders. — Grind  stones  are  usimI  only  for 
tliin-edo:ed   tools,  such   as  cutler\    and   wood-workin?,' 


( 


396 


n  •; 


THE  MECHANICAL  EQUIPMENT 


tools.  In  modern  shop  practice,  cutting  tools  are  no 
longer  ground  by  hand  on  an  emery  wheel  as  for 
merly  Correct  shape  and  proper  cutting  angles  are 
essential  factors  in  good  tool  performance,  and  these 
can  be  had  only  if  grinding  machines  are  used 
furthermore,  in  milling  cutters  and  reamers  it  is 
essential  that  all  the  teeth  be  ground  uniformly,  and 
this  cannot  be  done  by  hand. 

For  this  work  a  large  number  of  tool  grinders  have 
been  developed,  which  fall  into  three  general  classes: 
I^irst,  cutter  and  reamer  grinders,  for  sharpening  the 
multiple  edges  of  milling  cutters  and  reamers.     In  ^ 
this  type  the  tool  is  mounted  on  centers  or  an  an 
arbor  and  each  face  is  brought  for  grinding,  up  to  a 
delmite  position,  which  is  determined  by  a  stop     In 
this  way  uniformity  is  obtained  for  the  various  teeth 
Second,   twist-drill   grinders.     In   these,   the  drill   is 
carried  on  a  holder,  which  is  set  at  an  angle  of  about 
60  degrees  to  the  face  of  the  wheel,  and  which  is 
then  given   a   rocking   and   sliding  motion   as   it   is 
inoved  past  the  wheel.    Thus  a  slightlv  relieved  con- 
ical surface  is  produced.     The  drill  is  then  turned 
oveT  and  the  other  flute  is  ground,  provision  being 
made  that  the  two  surfaces  shall  be  alike.     Third 
umyersal   tool  grinders,  which   are  used  to  sharpen' 
all  kinds  of  lathe,  planer,  and  shaper  tools.    The  tool 
IS  clamped  into  a  holder,  which  can  be  rotated  about 
horizontal  and  vertical  axes,  which  is  also  capable  of 
sliding.     The  relationship  between  the  various  move- 
ments is  complex,  but  they  are  under  the  control  of 
adjustments  that  can  be  so  set  that  exact  shapes  and 
angles   can   be   ground   by   comparatively   unskilled 


GRINDING,  AND  GRINDING  MACHINERY      397 

labor.    With  them  it  is  possible  to  grind  any  face  at 
any  angle,  and  to  duplicate  the  pattern  indefinitely. 

Polishing  and  Buflfing. — Polishing  and  buffing  are 
finishing  operations  somewhat  allied  to  grinding.  No 
attempt  is  made,  however,  by  means  of  them  to  alter 
or  control  the  form  of  the  piece;  they  are  used  merely 
in  polishing  the  surface  or  in  preparing  it  for  plat- 
ing or  for  some  other  surface  finish,  such  as  blueing 
or  lacquering.  Polishing  wheels  often  are  made  of 
wood  and  have  around  their  circumference  leather 
strips  that  are  impregnated  with  emery  or  other 
abrasive  material.  Another  type  of  wheel  is  made  of 
steel,  and  is  about  12  inches  in  diameter  and  21/2 
inches  across  the  face;  over  the  face  is  a  strip  of  cloth 
carrying  the  abrasive,  which  may  be  changed  from 
one  grade  to  another  or  renewed  when  worn.  Wooden 
and  steel  wheels  are  used  on  work  where  it  is  neces- 
sary to  maintain  good  edges.  The  steel  wheels, 
which  are  safer  and  generally  more  economical,  are 
used  largely  in  cutlery  manufacture. 

Buffing  wheels  are  made  of  disks  of  leather — or  some- 
times of  cloth,  such  as  canvas,  muslin,  or  felt.  They 
are  clamped  between  two  steel  plates,  and  their  outer 
edges  are  impregnated  with  grinding  material,  rouge, 
and  the  like.  Wheels  of  this  kind  are  used  in  plain 
stands,  similar  to  those  shown  in  Figure  141,  and  the 
work  is  manipulated  by  hand.  Canvas  and  muslin 
wheels  are  used  for  polishing  irregular  pieces,  as  the 
wheels  are  soft  and  when  the  work  is  pressed  against 
them  they  will  conform  to  a  curved  surface.  Belts 
faced  with  grinding  dust,  which  run  from  2000  to 
2500  feet  per  minute,  are  also  used  with  good  results. 


Ji,  :^I 


BROACHING  AND  PRESS  WORK 


399 


CHAPTER  XXII 
BROACHING  AND  PRESS  WORK 

The  Broaching:  Process.— In  its  usual  application 
the  broaching  process  consists  in  forcing  an  elongated 
cutting  tool,  which  has  a  varying  cross-section,  and 
multiple  cutting   edges   along   the   sides,   through   a 
hole  already  formed,  thereby  changing  the  shape  of 
the  hole.     Formerly  the  broaching  tool  was  pushed 
through  by  a  press,  and  for  some  purposes— provided 
the  tool  can  be  very  short— this  is  still  done.    Nearly 
all  broaching,  however,  is  now  done  bv  pulling  the 
broach  through  the  hole.     The  initiafhole  is  ordi- 
narily drilled  at  right  angles  to  some  face  already 
machined,  as  in  the  majority  of  the  samples  shown 
in  Figure  150,  but  it  may  be  forged  or  rough-cored 
and  of  rectangular  or  other  shape,  as  in  the  case  of 
the  steel  revolver-frame  and  the  cast  iron  stand,  shown 
at  the  left.    Typical  broaching  tools  for  pulling  cuts 
are  shown  at  each  side  of  the  illustration. 

The  broaching  process  is  applicable  in  finishing 
square,  hexagonal,  or  odd-shaped  holes,  in  cutting 
single  or  multiple  key-ways  in  hubs,  and  in  forming 
the  teeth  of  small  internal  gears,  ratchets,  and  the 
like.  It  was  formerly  used  almost  entirely  for  in- 
terior work,  but  recently  has  been  extended  to  ex- 
terior work;  it  may  be  used  in  broaching  the  teeth  on 

398 


small  spur  gears  when  the  quantities  required  are 
large  enough.  The  chief  disadvantages  of  the  process 
are  the  high  cost  of  the  broaching  tools  and  the  un- 
certainty of  their  life,  but  these  are  much  more  than 
offset  by  its  speed  and  accuracy,  and  its  adaptability 
in  connection  with  a  wide  variety  of  irregular  forms, 
as  well  as  by  the  fact  that  the  work  can  be  done  by 
comparatively  unskilled  labor. 

It  is  said  that  broaching  was  first  used  by  Mr. 
R.  S.  Lawrence,  at  the  Sharps'  Rifle  Works,  in  Hart- 
ford, about  1853,  and  for  many  years  it  was  employed 
only  in  the  manufacture  of  guns  and  similar  articles. 
All  of  the  early  broaching  tools  were  pushed  through 
the  work  by  a  press;  consequently,  since  the  tools 
were  under  compression,  they  had  to  be  short  and 
of  fairly  large  cross-section,  or  they  would  buckle  and 
break.  In  good  practice  not  more  than  from  .001  to 
.003  inch  of  the  metal  should  be  removed  per  cutting 
edge,  and  sufficient  space  should  be  left  between  the 
tools  for  the  chips  to  accumulate  during  the  cut, 
which  means  that  they  cannot  be  much  less  than 
five-eighths  of  an  inch  apart.  Therefore,  when  there 
is  a  marked  change  in  the  shape  of  the  hole,  a  long 
succession  of  cutting  edges  is  required. 

Since  push-broaches  cannot  be  made  over  a  foot 
long,  however,  in  the  early  days  of  broaching  the 
work  had  to  be  divided  among  a  number  of  broaches 
which  were  used  in  succession;  the  first  one  started 
with  the  original  round  hole,  and  each  succeeding  one 
continued  the  operation  from  where  the  previous  one 
had  left  it.  Sometimes  as  many  as  ten  or  a  dozen 
broaches  were  required.     The  handling  of  so  many 


400 


THE  MECHANICAL  EQUIPMENT 


tools  involved  considerable  labor,  and  more  or  less 
danger  of  breaking  them  if  they  were  used  in  a 
wrong    order.      Even    under    these    handicaps    the 
broaching  process  produced  certain  kinds  of  work 
much  more  cheaply  and  satisfactorily  than  any  other 
method     In  modern  manufacture  the  broach  is  pulled 
through  the  work;  consequently  it  is  under  tension 
only,  and  may  be  any  length  convenient  to  handle. 
Ihus   the   danger  of  breakage   is  lessened,   and   the 
number  of  tools  to  be  handled  is  reduced.    This  mod- 
ern type  of  broach   has  practically   superseded   tho 
other  and  less  convenient  one. 

The   Broaching   Machine.-The   modern   form    of 
broaching  machine  is  shown  in  Figure  149     It  con 
sists  of  a  square,  box-like  upright   or  standard,   a, 
which  contains  the  operating  mechanism,  and  a  Ions 
horizontal   extension,   b,   of   U-shaped    cross-section 
Between  the  upper  ends  of  the  U  are  guides  carrv- 
mg  a  draw-head,  c,  which  slides  backward  and  for- 
ward along  the  top  of  the  extension.    Secured  to  this 
head  IS  a  long  screw,  d,  which  can  just  be  seen  be- 
tween the  guides.    The  screw  is  fixed  in  the  draw-hea<l 
and  does  not  rotate.    The  power  to  operate  the  ma- 
chine  is   carried   from   the   pulleys    at    the    extreme 
right  through  a  shaft  to  a  pinion  in  the  casing  whiel. 
drives    the   large   gear,    e,    to    which    is    secured   a 
threaded  sleeve,  engaging  the  screw,  d 

The  revolution  of  this  gear  and  its  sleeve  moves 
the  screw  and  the  draw-head  to  the  right  to  make  a 
cutting  stroke.  At  the  end  of  the  extension,  b,  is  an 
annular  finished  face,  f,  which  is  perpendicular  to 
the  motion  of  the  draw-head.     This  face  carries  a 


BROACHING  AND  PRESS  WORK 


401 


FIG.    149.      BROACHING   MACHINE 

suitable  work-holder,  g,  one  kind  is  shown  in  place, 
and  others  are  shown  in  the  pan  below.  The  work  to 
be  cut  is  set  into  the  work-holder,  g,  and  a  broach- 
ing tool  similar  to  the  one  shown  at  a.  Figure  150, 
is  inserted  through  the  initial  hole  in  the  piece  and 
keyed  to  the  draw-head  by  means  of  a  loose  key 
slipped  through  the  slot,  b,  Figure  150. 

Broaching  Tools.— Figure  150  shows  four  broaches; 
in  the  one  at  a,  the  shape  gradually  changes  from 
round  at  the  upper  end  to  square  at  the  lower  end. 
This  type  would  be  used  for  such  a  hole  as  that 
shown  at  c.  The  broach,  d,  would  be  used  for  cutting 
a  series  of  notches  or  splines,  as  shown  at  e.  For  a 
single  key-way,  as  at  f,  a  broach  of  the  type  shown 
at  g  would  be  used.     This  is  rectangular  in  cross- 


400 


THE  MKrHAXlfAL  KQUIPMENT 


tools  involved  considerable  labor,  and  more  or  les. 
danger   of  breaking   them   if   thev    were   used   in   u 
wrong    order.      P>en    under    ti.es..    handioaps    11,. 
broaching  process   produced   certain    kin.is   of   work 
much  more  cheaply  and  satisfactorily  than  anv  oth(.r 
metho.  .    I„  modern  manufacture  the  broach  is"  pulled 
througl,   (be  work;  consecpiently  it   is   nn.l.M-   t<.nsi«„ 
o^'ly,  and   may   b,.  any   length   convenient   to   han.H,. 
I  bus   the   danger  of   breakage   is  less,.,,...!,   an.l    ll„. 
number  of  tools  to  be  han.lled  is  red,„-ed.    Tbi<  nu..i 
ern   type   of  broach    has   practically    supersede.l    Ih,. 
other  and  less  convenient  one. 

The    Broaching    Machine.-The    modern    form    oi 
broaching  machine  is  shown  in  Figure  14!).     It  ,-,„, 
s.sts   of   a   square,   box-like   upright    or   stan.ianl,   a. 
which  contains  the  operating  mechanism,  an.!  a  ion- 
horizontal    extension,    b,    of    IJ-shape.l    cross-s,.ctio,r 
Betwe,.,,  the   n,,per  eiuls  of  the  V  are  gui.les  earrx  ' 
ing  a  draw-iiead,  c,  uhicli  slides  backward  and   foV 
ward  along  the  top  of  the  extensi<.n.    Seenred  to  thi< 
head  IS  a  long  screw,  .1,  whi<-b  can  just  be  seen  be 
tween  the  guides.    The  .«crew  is  fixe.l  in  the  draw-hea,l 
and  does  not  rotate.     The  power  to  operate  the  ma 
cb.ne    ,s    earried    from    the    pulleys    at    the    ..xtrem. 
right  through  a  shaft  to  a  pinion  in  th,.  casing-  wbieh 
drives    the    large    gear,    e,    to    wbi(-h    is    s.-einvd    a 
Ihreaded    sleeve,   engaging  the   screw,   d. 

The  revolution  of  this  gear  ami  its  sleeve  move 
the  screw  and  the  .Iraw-h<.ad  to  the  ri-ht  to  mak..  . 
cutting  stroke.  .\t  the  <.nd  of  the  extension,  1,  i.  ,, 
annular  finished  face,  f,  whieh  is  perpendicular  U 
the   molion   of   the   draw-head.      This   face   carries    , 


BKOACHINf!  AND  PHKSS  WOUK 


401 


FlU.    149.       BKOACHINd    MACHINE 

suitable  work-holder,  g,  one  kind  is  shown  in  place, 
and  others  are  shown  in  the  i)an  below.  The  work  to 
be  cut  is  set  into  the  work-holder,  g,  and  a  broach- 
ing loo!  similar  to  the  one  shown  at  a.  Figure  l.'jO, 
is  inserted  through  the  initial  hole  in  the  piece  and 
keyed  lo  llie  draw-head  by  means  of  a  loose  key 
sjipjied  tiirougii  th(>  slot,  1),  Figure  150. 

Broaching  Tools.— Figure  laO  shows  four  broaches; 
in  the  one  at  a,  the  shape  gradually  clianges  from 
round  at  the  upper  eiul  to  scpiare  at  the  lower  end. 
This  type  would  be  used  for  sucli  a  hole  as  that 
shown  at  c.  The  broach,  d,  would  be  used  for  cutting 
a  series  of  notches  or  syilines,  as  shown  at  e.  For  a 
siiigl(.  key-way,  as  at  f,  a  broach  of  the  type  shown 
at   g  would  be  used.     This  is  rectangular  in   cross- 


BROAC  KING  AND  PRESS  WORK 


403 


FIG.   150.      BROACHES  AND  SAMPLES  OF  BROACHING  WORK 

402 


section,  with  the  cutting  teeth  along  one  edge  only. 
The  piece  to  be  cut  is  mounted  on  a  projecting  stud, 
a,  Figure  151,  on  the  work  holder,  which  is  slotted 
at  b  to  receive  the  broach  and  guide  it  so  that  only 
the  cutting  edges  can  project.  The  small  end  of  the 
broaching  tool  is  inserted  through  the  work  and  the 
slot,  b,  in  the  supporting  stud,  and  secured  to  the 
draw-head.  The  handle,  i.  Figure  149,  ife  then  thrown 
over,  and  the  h«ad,  carrying  the  broach  with  it, 
moves  to  the  right.  The  teeth  are  set  on  an  incline; 
as  the  motion  starts,  the  teeth  begin  to  appear  above 
the  surface  of  the  stud,  a,  and  cut  deeper  and  deeper 
until  the  full  depth  is  reached.  The  last  few  teeth, 
c,  are  the  final  shape  required,  and  serve  to  bring 
the  work  accurately  to  size. 

This  feature  in  broaching  tools  accounts  in  large 
measure  for  the  accuracy  of  the  process.  The 
previous  cutting  edges  leave  little  work  for  the  siz- 
ing edges  to  do  and  if  the  first  of  these  wears,  the 
second  can  take  up  its  work,  and  so  on,  until  the 
last  one  has  been  worn  out.  When  the  broach  has 
been  pulled  all  the  way  through  the  work  and  holder, 
it  lies  in  the  extension,  b.  Figure  149.  It  is  removed 
from  the  draw-head;  then  the  handle,  i,  is  reversed, 
.and  the  draw-head  is  brought  back  to  the  starting 
position  by  a  rapid  return  traverse.  A  new  piece 
is  set  in  place,  the  broach  is  inserted  through  the 
hole  in  the  work  and  secured  once  more  to  the  head, 
and  the  machine  is  again  ready  to  start.  The  broach- 
ing process  is  not  confined  to  straight  cuts;  helical 
cuts  also  may  be  made,  provided  the  pitch  of  the 
helix  is  not  too  steep. 


HROAcniNCJ   AM)   PKKSS  WORK 


40:; 


Fir,.    150.      BROACHES  AND   SAMIM.FS  OF  BROArHIXr;   WORK 

402 


xcclion,  with  the  ('ntt'ni,u  Icctli  alon^  one  (mI^o  only. 
Tlie  piece  to  bo  cut  is  mounted  on  a  projecting  stud, 
a,  Figure  151,  on  the  work  liolder,  which  is  slotted 
at  ])  to  receive  the  broach  and  gui(h»  it  so  that  only 
the  cutting  inhj^ea  can  project.  The  small  end  of  the 
hroaching  tool  is  inserted  through  the  work  and  the 
slot,  b,  in  the  supporting  stud,  and  secured  to  the 
draw-head.  The  handle,  i,  Figure  149,  is  then  thrown 
over,  and  the  head,  carrying  the  broach  with  it, 
moves  to  the  right.  The  teeth  are  set  on  an  incline; 
as  the  motion  starts,  the  teeth  begin  to  api)ear  above 
the  surface  of  the  stud,  a,  and  cut  deeper  and  deeper 
until  the  full  depth  is  reached.  The  last  few  teeth, 
c,  are  the  tiiud  shape  recjuired,  and  serve  to  bring 
the  work  accui*ately  to  size. 

This  feature  in  broaching  tools  accounts  in  large 
measure  for  the  accuracy  of  the  process.  The 
previous  cutting  edges  leave  little  work  for  the  siz- 
ing i'iUfj!:i^ii  to  do  and  if  the  tirst  of  these  wears,  the 
second  can  take  up  its  work,  and  so  on,  until  the 
last  one  has  been  worn  out.  When  the  broach  has 
l)een  pulled  all  the  way  through  the  work  and  holder, 
it  lies  in  the  extension,  b.  Figure  149.  It  is  removed 
from  the  draw-head;  then  the  handle,  i,  is  reversed, 
and  the  draw-head  is  brought  back  to  the  starting 
position  by  a  rapid  return  traverse.  A  new  piece 
is  set  in  place,  the  broach  is  inserted  through  the 
hole  in  the  work  and  secured  once  more  to  the  head, 
and  the  nuichine  is  again  ready  to  start.  The  broach- 
ing process  is  not  confined  to  straight  cuts;  helical 
cuts  also  may  be  made,  provided  the  pitch  of  the 
helix  is  not  too  steep. 


BROACHING  AND  PRESS  WORK 


405 


404 


Broaching  machines  of  the  draw-head  type  are 
capable  of  making  strokes  np  to  50  inches,  so  that 
long  broaches  can  be  used  with  the  resulting  saving 
in  both  tool  expense  and  operation.  This  process 
is  being  applied  to  larger  and  heavier  work,  since 
its  economy  of  operation  and  accuracy  of  output 
make  it  a  valuable  method  wherever  there  are  quan- 
tities sufficient  to  justify  the  expense  of  the  tools. 

Punches  and  Dies. — ^Press  operations,  which  are 
done  with  punches  and  dies,  may  be  either  cutting 
or  forming,  or  a  combination  of  both.  The  cutting 
is  always  a  shearing  action,  as  in  cutting  up  bar 
or  sheet  stock,  punching  holes  of  almost  any  shape, 
or  trimming  off  the  raw  edges  of  pieces  after  they 
have  been  formed.  The  shaping  or  forming  opera- 
tions are  in  reality  cold  forging,  and  comprise  bend- 
ing, forming,  bulging,  embossing  or  coining,  cupping 
and  drawing,  or  heading  and  upsetting.  Nearly  every 
operation  calls  for  a  different  die,  and  we  can  describe 
here  only  a  very  few  of  the  better  known  types.  These 
are  used  generally  on  sheet-metal  stock  of  steel, 
wrought  iron,  brass,  copper  and,  in  the  case  of 
jewelry,  of  the  precious  metals.  The  tools  consist 
of  two  main  parts,  a  die  of  one  or  more  pieces,  which 
is  secured  to  a  fixed  bed  in  the  machine,  and  a  punch 
carried  in  a  reciprocating  head,  the  motion  of  which 
is  controlled  by  some  form  of  clutch. 

One  of  the  simplest  forms  is  the  plain  blanking 
die.  Figure  152,  which  consists  of  a  die,  a,  with  cut- 
ting edges,  b,  formed  to  give  the  proper  shape,  and 
the  corresponding  punch,  c.  The  strip  from  which 
the  blank  is  to  be  cut  is  laid  over  the  opening;  the 


»  ; 


i 


406 


THE  MECHANICAL  EQUIPMENT 


BROACHING  AND  PRESS  WORK 


407 


I 


punch  descends  through  the  die,  carrying  the  blank 
with  it.  Generally  there  must  be  a  stripping  piece, 
d,  which  reaches  over  the  top  of  the  sheet  metal  and 
holds  it  in  place  as  the  punch  rises.  This  piece  strips 
the  metal  off  the  punch  and  leaves  the  sheet  free  to 
be  fed  along  for  the  next  piece.  Several  punches  may 
be  combined  in  one  fixture  and  all  do  the  same  kind 
of  work,  or  they  may  perform  a  succession  of  opera- 
tions one  after  the  other.  When  they  perform  the 
same  kind  of  work,  they  are  known  as  gang  dies; 
when  they  work  in  series,  each  punch  making  its  own 
cut,  they  are  known  as  follow  dies.  The  simplest 
form  of  bending  die  is  shown  in  Figure  153.  The 
face  of  the  die  is  shaped  to  conform  to  the  contour 
desired,  and  the  punch  forces  the  work  down  into  it. 
The  action  is  so  simple  that  it  needs  no  explanation. 

Two  or  more  bending  operations  may  be  performed 
in  a  compound  bending  die,  as  shown  in  Figure  154. 
In  the  one  shown,  the  work  is  carried  down  into  the 
die  by  the  punch,  a,  and  held  there  while  the  beveled 
fingers,  b,  acting  upon  slides,  c,  in  the  die,  force  them 
inward  and  produce  the  bend,  d.  On  the  upstroke 
of  the  head  the  slides,  c,  are  thrown  out  by  springs; 
the  finished  piece  rises  with  the  punch,  and  may  be 
slipped  off  when  it  is  clear  of  the  die.  When  the 
punch  performs  several  operations,  as  in  this  case, 
it  IS  usually  necessary  to  introduce  a  spring  connec- 
tion, e,  which  will  allow  the  main  portion  of  the 
punch  to  descend  and  effect  the  second  motion  while 
the  punch  stays  at  rest.  Remarkable  ingenuity  is 
displayed  in  the  design  of  dies  of  this  character, 
which  are  sometimes  quite  intricate. 


Figure  155  shows  a  double-action  die  combining 
cutting  with  drawing,  which  is  but  a  form  of  bend- 
ing. In  this  instance  there  are  two  sliding  heads, 
one  of  which  carries  the  punch,  a,  which  cuts  out  a 
round  disc  by  shearing  against  the  cutting  edges,  b, 
of  the  die,  c.  The  punch,  d,  then  descends  and 
pushes  the  blank  through  the  hole,  e,  forming  the 

shell  as  shown. 

Plain  drawing  dies  repeat  the  action  of  the  parts 
c  and  d  as  the  shell  is  progressively  forced  through 
holes— each  smaller  than  the  one  immediately  preced- 
ing—and drawn  out  from  the  shallow  cup  into  a 
longer  one  and  even  into  a  tube.  Such  redrawmg 
dies  are  characteristic  tools  in  the  manufacture  ot 
cartridge  shells.  All  materials  drawn  in  dies  m  this 
way  must  be  annealed  from  time  to  time  as  the  work 
progresses,  because  after  a  certain  percentage  of 
*^ drawing  down"  they  become  brittle  and  their  duc- 
tility must  be  restored.  This  is  done  by  heating 
them  to  a  red  heat  and  allowing  them  to  cool. 

Figure  156  shows  a  combination  die  used  for  cut- 
ting a  blank  and,  at  the  same  stroke,  turning  down 
the  edge  and  drawing  the  piece  into  the  required 
shape.  The  work  is  blanked  by  the  cutting  punch 
a,  and  formed  to  the  right  shape  by  b  and  c.  The 
former  holds  the  piece  by  spring  pressure  against 
the  block,  c,  while  the  punch,  a,  continues  to  descend, 
and  draws  the  work  into  the  required  shape.  The 
ring,  d,  acts  as  an  ejector,  throwing  out  the  piece 
as  the  punch  rises  on  the  return  stroke.  The  flange 
or  edge,  e,  which  is  left  turned  out,  is  sure  to  b6 
irregular  in  shape.     When  it  is  necessary  to  have 


BROACHING  AND  PRESS  WORK 


409 


I' I 


I 


I 


this  smooth,  the  edge  is  cleaned  off  in  a  trimming 
die  somewhat  similar  to  that  shown  in  Figure  lol. 

Figure  157  shows  a  bulging  die  which  enlarges  a 
cup,  similar  to  that  formed  in  Figure  155,  to  the 
rounded  shape  shown.  The  drawn  shell  is  placed 
over  the  mushroom  plunger,  a,  in  the  die  and  when 
the  punch  descends  the  rubber  disc,  b,  is  forced  out, 
expanding  the  shell  into  the  curved  chamber  formed 
hy  the  punch  and  the  die.  As  the  punch  rises,  the 
rubber  returns  to  its  original  form  and  the  expanded 

work  is  then  removed.  ,         r,  jjo, 

The  most  accurate  type  of  die  is  the  sub-press  die, 
shown  in  Figure  158.    In  all  the  dies  above  described, 
the  machine  is  depended  upon  for  the  accurate  regis- 
tering of  the  punch  with  the  die.    The  sub-press  die 
is  self-contained;  the  punch,  a,  slides  in  an  upright, 
b,  which  is  secured  to  the  base,  c.    The  only  function 
of  the  machine  is  to  depress  the  top  of  the  punch,  a; 
correct  alignment  is  obtained  from  the  proper  regis- 
tering of  the  pieces  a,  b,  and  c.    Dies  of  this  char- 
acter are  used  in  the  manufacture  of  watches,  for 
punching  out  wheels  and  other  parts,  and  they  can 
be  made  to  do   work   requiring   extreme   accuracy. 
The  finer  parts  (not  shown)  are  secured  to  the  taces 
e  and  f  of  the  punch  and  die. 

Types  of  Presses.— The  simplest  form  of  press  is 
the  foot  press,  shown  in  Figure  159.  These  machmes 
are  used  in  jewelers'  work,  and  for  light  operations 
on  small  pieces.  They  may  be  mounted  on  independ_ 
ent  stands,  as  shown,  or  in  rows  along  a  bench,  and 
are  usuallv  operated  by  girls  or  boys.  The  die  is 
set  on  the  base,  and  the  punch  is  carried  in  the  slid- 


410 


THE  MECHANICAL  EQUIPMENT 


ing  head,  a,  mounted  in  the  frame  of  the  machine. 
The  motion  is  derived  from  a  toggle  joint  actuated 
by  a  heavy  pendulum,  b,  which  is  pushed  back  by 
the  foot  treadle,  c.  By  means  of  the  adjusting  screw, 
d,  the  head  may  be  raised  or  lowered  to  accommodate 
different  heights  of  work.  In  another  type  of  hand 
press  which  is  widely  used,  the  head  is  forced  down 
by  means  of  a  sharp-pitched  screw,  which  occupies 
the  place  of  the  adjusting  screw,  d.  Across  the  top 
of  this  screw  is  a  horizontal  arm,  which  carries  at 
each  end  a  heavy  cast-iron  ball.  A  handle  drops 
down  from  the  arm  to  a  point  within  reach  of  the 
operator,  who,  by  pulling  this  handle,  revolves  the 
screw  and  the  heavy  weights  and  forces  the  head 
down  against  the  work. 

For  larger  work  the  belt-driven  press.  Figure  160, 
is  used.  This  consists  of  a  heavy  C-shaped  frame 
which  leaves  the  sides  clear  so  that  strip  stock  can 
be  fed  across  the  die  from  side  to  side.  When  the 
back  is  open,  as  at  a,  the  press  is  known  as  an  open- 
back  press.  The  opening  permits  light  from  the  back 
of  the  machine  to  fall  on  the  die,  and  also  provides 
an  egress  through  which  the  stamped  articles  may 
be  discharged.  In  this  type  of  press  the  main  frame, 
b,  is  usually  separate  from  the  legs,  c,  and  is  clamped 
to  them  by  means  of  a  fitted  connection,  d,  which 
is  on  the  arc  of  a  circle. 

By  the  turning  of  the  worm,  e,  in  the  base,  the 
frame,  b,  may  be  tilted  backward  at  an  angle,  an 
advantage  often  convenient  in  connection  with  cer- 
tain types  of  work,  since  the  finished  piece  will  then 
slide  away  from   the  opartor  and   out   through   the 


FIG.    159.      FOOT  PRESS 


FIG.    160.      BELT-DRIVEN   OPEN 
BACK  PRESS 


I 


FIG.    161.      BACK-GEARED 
PILLAR  PRESS 


PIG.   162.      KNUCKLE-JOINT 

PRESS  411 


410 


ing  head,  a,  niountod  in   fho  frame  ol'  tlie 


The  motion 
by  a  heavy 
the  foot  treadl 


machiu< 


is  derived   from  a  toaal 


r^rt 


diffe 


lo  joint  actuated 

pendnhim,  b,  whicJi   is  pushed  back  by 

c,  c.     By  means  of  the  adjusting  screw, 

owered  to  accommodate 


d,  the  liead  mav  be  raised  or  1 


i-ent  lieights  of  work.      I 


press  whicli  is  wi(k-lv 


n  anotlier  tyi)e  of  han<i 


I 


usi'd,  tlie  liead  is  forced  d 


own 


)y   means   of  a   sharp-pitched   scr 


ew 


w 


the  pi, 
of  tl 


ice  of  the  adjusting  screw,  d.     A 


hicli   occupie 
the  t 


cross 


on 


lis 


I 


crew   IS  a   horizontal   arm,    wliicli   carries  at 


each    end    a    lieavv    east- 
d 


iron    ball.      A    handh'   drops 
down  from  the  arm   to  a   point   witliin   reacli   of  Uw 

e,    revolves   the 
eavy    weiglits   and    forces    \]w   luwid 


operator,    wlio,   hy   ])ulling  this   liandl 
screw    and    tlie    h 


down  against  the  worl> 


For  I 


irger  work  the  belt-driven  press,  F 


IS    used.      Thi 


'iiiure  Kid. 


which   leaves  tlie  sides  cI 


s   consists   of  a   heavy   C-shaped    fi 


amc 


ear  so  that  strip  stock  can 
be  fed  across  the  die   from  side  to  sid(^     AVlien   the 


bad 


back 


k  is  open,  as  at  a,  the  press  is  known  a: 


pre 


ss. 


^ri 


an  open 
le  opening  i)ermits  light  from  the  back 


of  the  machine  to  fall   cm  the  d 


an   eirress 


tl 


ie,  and  also  provide 


irougli    which    the   stamped    articl 


be  dischai'ged.     Jn  this  tyj)e  of 


es   ma\ 


press  the  main  fram 


, "■^^'..     ...  i.M.-  i^|M'  ui   (jiess  riie  main  Trame, 

b,  is  usually  separate  from  the  legs,  c,  and  is  clamped 


to   them    by   means   of  a   fitted  connection,   d,   whicl 
is  on  tlie  arc  of  a  circle. 

By  the   turning  of  the  w 
frame,   b,   may   be  tilted   backw^ard   at 


orm,  e,  in   the   base,   the 

an   angle,   an 

in   connection   with   cer- 


advantage  often   convenient 

tain  types  of  work,  since  the  finished  piece  will  then 

slide   away   from    the   opartor   and    out   throuah    tin 


iKi.   IT)!).     FOOT  r-in:ss 


fk;.   IfiO.     rklt-dkivi:n  oim:n 

BACK  PRESS 


Fir,.    161.       BACK-iiKARF.n 
IMl.LAR   PRF.SS 


Fir,.    162.       KN'T'CKLE-.IOINT 
PRESS  411 


412 


Tlli:  MECHANICAL  EQUIPMENT 


BROACHING  AND  PRESS  WORK 


413 


!| 


g 


opening  in  the  back  into  a  drum  or  receptacle  behind 
the  machine.  The  punch  head,  f,  is  operated  through 
a  connecting  rod  from  the  crank,  g,  between  the 
housings  on  the  top  of  the  frame.  This  crank  is  part 
of  shaft,  which  extends  to  the  right  and  carries  the 
driving  pulley.  The  pulley  is  generally  made  with  a 
heavy  rim,  so  that  it  acts  as  a  flywheel  as  well.  It 
is  not  keyed  to  the  shaft  but  rotates  freely,  except 
when  a  clutch  on  the  side  of  the  machine  between  the 
pulley  hub  and  the  frame  is  thrown  in. 

This  clutch  does  not  show  in  the  figure.  It  is 
operated  by  the  foot  treadle,  h,  shown  below.  Much 
thought  has  been  given  to  the  subject  of  press 
clutches,  as  the  work  they  are  called  upon  to  do  is 
very  severe.  They  are  usually  arranged  to  lock  the 
pulley  to  the  shaft  when  the  treadle  is  depressed  and 
held  there.  If  the  treadle  is  depressed  and  the  foot 
is  removed  at  once,  the  crank  shaft  will  make  one 
revolution  and  stop  automatically  at  the  top  of  the 
return  stroke,  in  the  position  shown.  The  work  is 
then  fed  forward  and  the  treadle  is  depressed  again. 
For  continuous  operation  it  is  necessary  only  to  keep 
the  treadle  depressed.  The  connecting  rod  is  made 
in  two  sections,  which  may  be  clamped  together  by 
the  screw,  i.  Thus  an  adjustment  for  length  is  given 
which  allows  setting  the  head  to  different  heights  for 
varying  jobs. 

Figure  161  shows  a  straight-sided  or  pillar  press, 
which  is  much  stronger  than  the  one  just  shown,  but 
in  general  not  so  convenient.  Here  the  connection 
between  the  base  which  carries  the  die  and  the  bear- 
ings above,  is  made  by  two  straight  members  a,  a, 


which  are  free  from  the  bending  strain  incident  to 
the  open-back  type.  This  press  is  back-geared,  the 
belt  runs  on  tight  and  loose  pulleys  at  the  left,  and 
the  flywheel  is  separate  from  the  pulleys.  The  pul- 
leys and  the  flywheel  are  carried  on  a  separate  shaft 
at  the  back  of  the  machine,  and  this  shaft  has  a 
pinion  at  the  opposite  end  engaging  with  the  large 
spur  wheel  at  the  right.  The  clutch  is  located,  as 
in  the  machine  just  described,  at  b,  between  the 
frame  and  the  hub  of  the  large  gear. 

Figures  160  and  161  both  show  single-action 
presses;  that  is,  there  is  one  head  with  its  connect- 
ing rod  and  crank.  In  a  double-action  die,  such  as 
that  shown  in  Figure  155,  it  is  necessary  that  there 
be  two  heads.  One  of  these  is  usually  arranged  to 
slide  inside  the  other,  and  the  shaft  above  has  three 
crank  pins — one  in  the  middle,  which  operates  one 
head;  and  one  on  each  side,  which  act  together  and 
operate  the  other  head.  Such  presses  are  known  as 
double-action  presses.  Triple-action  presses  are  also 
made,  in  which  the  third  motion  is  usually  given  to 
an  independent  head  that  acts  upward  through  the 
lower  die. 

A  still  more  powerful  type  of  press  is  the  knuckle- 
'joint  press.  Figure  162,  which  usually  has  the  pillar 
type  of  frame.  The  shaft,  however,  instead  of  driv- 
ing directly  down  to  the  head,  operates  a  toggle  or 
knuckle  joint.  The  upper  member,  a,  connects  with 
the  arch  of  the  frame,  and  the  lower  member,  b,  with 
the  head,  c.  A  short  link  extends  forward  from  the 
crank  on  the  main  shaft,  d,  to  the  joint  between  the 
toggle  members,  a  and  b.    Presses  of  this  type  have  a 


lIBii'' 


ll 


11 


r 


i 


414 


THE  MECHANICAL  EQUIPMENT 


very  short  stroke,  but  tremendous  power;  they  are 
used  for  embossing,  coining,  and  so  on.  Hydraulic 
presses,  also,  are  used  for  heavy  work,  especially 
where  the  stroke  is  long.  These,  however,  are  not 
used  so  much  for  cold  pressing  as  for  hot  forging. 
A  heavy  forging  press  is  shown  in  Figure  20. 

The  types  of  presses  are  often  subdivided  accord- 
ing to  the  use  to  which  they  are  put  and  the  methods 
of  feeding  the  work.  A  coining  press  is  a  knuckle- 
joint  press  especially  adapted,  as  the  name  implies, 
for  coining  work.  Trimming  presses  are  used  to  cut 
off  the  ragged  edges  of  pieces  that  have  been  blanked 
and  formed.  Other  types  are  called  multiple-punch- 
ing, notching,  or  perforating  presses,  according  to 
their  use.  A  cut-and-carry  press  has  multiple  plung- 
ers, each  of  which  does  a  different  operation.  The 
stock  is  fed  in  from  one  side  and  moved  across  from 
station  to  station  with  each  stroke  of  the  head,  and 
a  finished  piece  comes  out  on  the  other  side  at  every 
stroke.  In  a  dial-feed  press  a  circular  work-holder, 
or  dial,  rotates  about  a  central  stud  on  the  base;  it 
has  openings  or  stations  around  the  rim.  The  dial  is 
operated  automatically  by  the  punch,  and  the  oper- 
ator feeds  the  stations  on  the  side  toward  him  while 
work  is  being  performed  on  the  pieces  that  are  on 
the  other  side.  This  is  a  safe  and  rapid  form  of  feed, 
well  adapted  to  long  runs  of  standard  work. 

Safety.— Increasing  attention  is  being  given  to  the 
the  question  of  the  safety  of  the  operator  in  feeding 
punching  machinery.  With  no  class  of  machines  have 
accidents  been  more  frequent.  They  usually  come 
from  the  accidental  throwing  in  of  the  clutch,  from 


BROACHING  AND  PRESS  WORK 


415 


tlie  failure  of  the  operator  to  get  his  hand  away  from 
the  die  quickly  enough  after  he  has  thrown  the 
clutch,  or  from  an  attempt  to  readjust  the  work  on 
the  die  while  the  head  is  descending.  Many  safety 
devices  have  been  developed.  Some  of  them  provide 
an  automatic  stop  which  locks  the  head  so  that  it 
cannot  descend  until  the  operator's  hands  are  clear 
of  the  die.  Others  hold  the  clutch  until  the  operator 
throws  a  releasing  mechanism  which  requires  the 
use  of  both  hands.  And  in  another  form,  a  guard  is 
automatically  interposed  between  the  operator  and 
the  die  by  the  clutch-throwing  mechanism  or  by  the 
head  as  it  descends. 


V 


' 


;! 


I       II 


§l| 


^ 


CHAPTER  XXIII 
WOODWORKING   MACHINERY 

Types  of  Machines  Few;  Modifications  Many. — The 
natural  peculiarities  of  wood  constitute  a  factor  that 
has  strongly  influenced  the  design  of  the  machinery 
used  for  working  it  into  useful  shapes.  Obviously 
wood  cannot  be  cast  or  forged;  hence  woodworking 
machines  are  nearly  all  cutting  machines.  Wood  is 
comparatively  soft  and  brittle,  and  the  chips  clear 
themselves  easily;  therefore  high  speeds  (5000  to 
10,000  feet  a  minute)  are  the  rule,  with  correspondingly 
fast  feeds  and  high  power  consumption.  Such  speeds 
preclude  reciprocating  motion  between  the  cutter  and 
the  work;  the  lathe,  drill,  milling  and  grinding  ma- 
chines are  the  only  machine  tools  that  have  their 
counterparts  in  woodworking. 

In  spite  of  the  small  number  of  fundamental  ma- 
chines, each  type  has  been  modified  in  many  ways 
to  suit  special  conditions,  so  that  today  there  is  wide 
variety  in  the  methods  of  holding  and  feeding  the 
work,  and  in  the  arrangement  of  the  cutting  tools. 
Thus,  the  surfacer,  the  matcher,  the  moulder  and  the 
shaper*  are  developments  of  the  planer;  the  hollo w- 

*  Note.— These  names  must  not  be  confused  with  those  of  metal- 
working  machine  tools,  with  which  the  tools  here  mentioned  have  no 
connection. 

416 


WOODWORKING  MACHINERY 


417 


chisel  mortiser  is  a  form  of  borer;  the  circular  saw, 
in  effect  a  fast-running  milling  cutter,  is  used  in 
plain  and  universal  benches,  swing  frames,  tenoning 
machines,  log  mills,  and  so  on. 

Saws.— Some  form  of  saw  is  invariably  used  for 
cutting  lumber  roughly  to  shape.  The  circular  saw 
has  been  used  in  the  past  to  do  most  of  this  work, 
especially  when  straight  cuts  were  required.  The 
band  saw  has  now  superseded  it  in  many  cases.  The 
great  advantages  of  the  band  saw  are  its  thinness, 
by  virtue  of  which  it  wastes  only  one-third  as  much 
material  as  the  circular  saw,  and  its  narrowness, 
which  makes  it  suitable  for  use  on  curves  and  easy 
scroll  work  as  well  as  for  straight  lines.  A  plain 
band  saw  for  general  purposes  is  shown  in  Figure  163. 
The  cast-iron  C-frame  carries  an  upper  and  a  lower 
wheel,  a  and  b,  each  about  3  feet  in  diameter  and 
faced  with  leather;  the  upper  wheel  bearing  slides  in 
vertical  ways,  and  is  pushed  upward  by  a  spring  that 
keeps  the  correct  tension  in  the  saw,  c,  which  passes 
over  the  wheels.  The  lower  wheel  shaft  carries  both 
tight  and  loose  pulleys  on  the  rear  end,  over  which 
the  driving  belt  passes;  the  belt  shipper  for  starting 
and  stopping  the  saw  is  operated  by  the  handle,  d. 

The  work  is  laid  on  the  table,  e,  which  can  be 
tilted  from  zero  to  45  degrees,  by  a  hand  wheel  (not 
shown),  and  which  is  fed  by  hand  against  the  front 
edge  of  the  saw.  The  thrust  is  borne  by  the  roller 
guides,  f,  the  upper  one  of  which  can  be  placed  as 
close  to  the  work  as  convenient  by  lowering  the  post,  g. 
For  safety's  sake  both  wheels,  and  all  except  the  work- 
ing portion  of  the  saw,  should  be  inclosed,  as  shown 


418 


THE  MECHANICAL  EQUIPMENT 


I 


I 


in  the  figure.  The  saws  used  vary  from  1/2  to  21/2 
inches  in  width,  have  a  brazed  lap  joint,  run  at  a 
speed  of  5000  feet  a  minute,  and  consume  3  to  5 
horsepower. 

For  ripping  and  straight-edging,  a  heavier  ma- 
chine is  used,  with  a  saw  4  inches  wide,  and  an  ad- 
justable guide  or  ** fence''  is  attached  to  the  left  side 
of  the  table.  The  work  is  fed  automatically,  from 
30  to  125  feet  a  minute,  by  two  fluted  rolls  carried 
at  the  lower  end  of  the  post,  g. 

Band  Saw.— The  band  saw  is  desirable  for  re-saw- 
ing timbers  into  boards,  or  a  thick  board  into  two 
thin  ones,  on  account  of  its  narrow  slot,  or  kerf.  For 
this  purpose  an  in-feeding  and  an  out-feeding  pair 
of  vertical  feed  rolls  are  used.  All  the  rolls  are 
power-driven  and  can  be  adjusted  by  a  hand  wheel 
for  different  thicknesses  of  work.  For  sawing 
warped  surfaces,  such  as  ship  timbers,  a  special  saw 
is  used,  both  wheels  of  which  are  mounted  on  a  cir- 
cular housing  carried  on  roller  bearings  by  the  main 
frame.  The  saw  can  be  tipped  45  degrees  to  the  right 
or  left  while  working,  so  that  it  is  possible  to  cut 
almost  any  skew  shape  with  it. 

Circular  Saw.— In  spite  of  the  fact  that  the  band 
saw  can  be  used  in  a  variety  of  ways,  the  circular 
saw  is  very  often  used  in  preference,  especially  when 
many  long,  straight  cuts  must  be  made.  In  its 
simplest  form  it  is  used  in  a  plain  saw  bench,  which 
consists  of  a  four-legged,  or  box,  frame  supporting 
a  smooth  iron  or  wooden  table,  about  4  feet  by  6  feet, 
and  carrying  a  horizontal  arbor  on  which  is  mounted 
a  circular  saw  whose  upper  edge  projects  through 


.'•i  .1 

I*  .1 


418 


THE  ME(iIAXI('AI.  EQUIPMENT 


in  the  figure.  Tlie  saws  used  vary  fi-oin  i/^  to  2^. 
inches  in  widtli,  liavc  a  hrazed  lap  joiut,  run  at  a 
speed  of  nooO  feei  a  uiiuute,  and  consume  3  to  :> 
liorsepowcr. 

For  ripping  and  straight-edging,  a  Invivier  ni;i- 
ehine  is  used,  witli  a  saw  4  inches  wi(h',  and  an  ad 
justahk^  gui(h'  or  ''fence"  is  attached  to  tlie  left  si^lc 
of  tlie  table.  Tlic  work  is  Uh]  autonudically,  from 
:^0  to  12.")  IV(»t  a  ininut(\  hy  two  fluted  rolls  carried 
at  the  lower  end  of  the  post,  g. 

Band  Saw. — The  hand  saw  is  (h^sirahle  for  re-saw- 
ing timbers  into  ])oards,  or  a   thick   board   into   two 
thin  ones,  on  account  of  its  narrow  slot,  or  kerf.     For 
this   purpose   an    in-feeding   and    an    out-fe(Mling   pair 
of   vertical    feed    rolls    are    used.      All    tlu^    rolls    aro 
power-driven  and   can    be  adjusted   by  a  hand   wIkmI 
for    different     thicknesses     of     work.       For     sawin- 
warped  surfaces,  such  as  ship  tim])ers,  a  special  saw 
is  used,  botli  Avhec^ls  of  which  are  mounted  on  a  cir 
cnlar  housing  carried  on  roller  bearings  by  the  main 
frame.    Tlu'  saw  can  be  tij)])ed  45  d(»grees  to  the  riglil 
or  left   while   working,  so   that    it   is   possible  to   cul 
almost  any  skew  shape  with  it. 

Circular  Saw.— In  spite  of  the  fact  that  the  baii<l 
saw  can  be  used  in  a  variety  of  ways,  the  circid.'ir 
saw  is  very  often  used  in  preference^,  especially  when 
many  long,  straight  cuts  must  be  made.  In  its 
simplest  form  it  is  used  in  a  plain  saw  bench,  whidi 
consists  of  a  four-legg<'d,  or  box,  frame  supportinu^ 
a  smooth  iron  or  wooden  table,  about  4  feet  by  ()  feel, 
and  carrying  a  horizontal  arbor  on  which  is  mountcMl 
a    circular   saw    whose    upper    o(\o;^.    projects    throucrli 


420 


THE  MECHANICAL  EQUIPMENT 


WOODWORKING  MACHINERY 


421 


3  11 


ii 


1' 


a  narrow  slot  in  the  table.  A  long  fence  for  guiding 
the  work  is  clamped  to  the  top  of  the  table;  it  can 
be  shifted  for  ripping  different  widths,  and  can  be 
tilted  for  sawing  bevels. 

The  table  can  be  elevated  by  a  hand  wheel  or  by  a 
lever,  so  that  the  saw  blade  will  protrude  through 
the  top  of  the  work  no  further  than  is  necessary  to 
make  a  clean  cut.  The  smaller  sizes  are  hand-fed, 
but  for  heavy  ripping  and  edging  a  two-roll  feed  is 
used,  similar  to  that  on  band  saws.  A  chain  feed  is 
sometimes  used  when  a  straight  cut  is  absolutely 
essential.  Such  a  feed  consists  of  two  endless  chains 
which  travel  the  length  of  the  table,  one  on  each  side 
of  the  saw,  in  a  recess  made  for  the  purpose,  and 
return  underneath  through  the  frame.  Each  link  has 
a  serrated  surface,  against  which  the  work  is  pressed 
by  a  row  of  weighted  idlers  acting  from  above. 

Universal  Saw  Bench.— Gradual  development  of 
this  type  has  evolved  the  universal  saw  bench,  shown 
in  Figure  164.  The  table  consists  of  a  stationary 
section,  a,  and  a  moving  section,  b,  carried  on  rollers 
c.  Both  the  stationary  section  and  the  moving  sec- 
tion are  carried  on  a  rocker,  so  that  the  whole  table 
can  be  tilted  about  a  longitudinal  horizontal  axis 
through  the  saw  slit,  d.  Two  saws,  a  cross-cut,  e, 
and  a  rip,  f,  are  provided;  they  are  mounted  at  each 
end  of  a  yoke  (not  visible)  carried  in  bearings  in  the 
main  frame. 

By  the  turning  of  a  handwheel  the  yoke  is  swung 
in  its  bearings  and  either  saw  is  brought  into  operat- 
ing position.  Two  types  of  fence  are  provided:  the 
ripping  fence,  g,  which  can  be  clamped  at  any  angle 


and  at  any  distance  from  the  saw;  and  the  cut-off 
gauge,  h,  which  may  also  be  clamped  at  any  angle, 
and  which  is  provided  with  a  guide  strip  that  slides 
in  the  groove,  i.  All  fences  and  gauges  have  scale 
and  micrometer  adjusting  screws  for  making  accurate 
settings.  This  machine  is  most  useful  m  cabinet- 
making  and  pattern  shops,  where  the  degree  of 
accuracy  approaches  that  required  in  metal  working. 
Swing-Frame  Saw.— The  swing-frame  saw  is  pecu- 
liarly  fitted  for  cutting  off  to  standard  lengths,  as  m 
door,  sash,  and  box  factories.  The  work  rests  m  a 
fixed  position  on  a  table,  and  the  saw,  whose  arbor  is 
supported  in  the  lower  end  of  a  frame  that  hangs 
from  the  ceiling,  is  pulled  through  the  work  from 

back  to  front. 

Log  Mill.— A  special  apparatus,  known  as  a  log 
mill,  is  used  for  ripping  logs  and  rough  timbers  into 
boards.  It  has  two  main  parts:  the  husk,  a,  and  the 
carriage,  b  (Figure  165).  The  former  si:,.ports  the 
saw,  the  arbor,  and  the  feed  mechanism;  the  latter 
holds  the  log  and  feeds  it  past  the  saw.  The  arbor 
is  driven  directly  by  the  pulley,  c;  the  forward  feed 
is  obtained  by  pulling  the  lever,  d,  to  the  right.  This 
motion  feeds  the  frame  forward  by  means  of  a  pinion 
meshing  with  the  rack,  e.  For  the  return  feed,  or 
''gig,''  which  is  considerably  faster  than  any  of  the 
forward  feeds,  the  lever  d  is  pushed  to  the  left. 
The  gauge-roll,  f,  with  graduated  adjustment,  sup- 
ports the  left-hand  side  of  the  timber  as  it  approaches 
the  saw,  and  the  spreader  wheel  enters  the  kerf  and 
opens  it  enough  to  prevent  the  binding  of  the-  saw. 
The  carriage  is  a  timber  frame  which  travels  on 


lit 

II 


WOODWORKING  MACHINERY 


423 


rolls  that  are  either  stationary,  as  shown  in  the  illus- 
tration,  or  fastened  to  the  under  side  of  the  carnage 
stringers.  Bolted  to  it  are  a  number  of  head-blocks, 
h  spaced  about  five  feet  apart,  which  support  the 
log  on  its  under  side;  its  right-hand  side  rests  against 
the  uprights,  i,  fastened  to  the  set  beam,  j.  The  log 
is  clamped  rigidly  to  the  uprights  by  hooks,  or 
^^dogs,"  of  various  styles,  and  is  **set"  or  shifted 
across  the  carriage  by  the  handle,  k.  The  scale,  1, 
indicates  the  distance  between  the  uprights  and  the 
saw.  The  foot  lever,  m,  brings  into  action  a  device 
that  ** backs"  the  set  beam  to  take  on  a  new  log 
while  the  carriage  is  gigging. 

Gang  Saw.— The  gang  saw,  for  cutting  logs  into 
lumber,  constitutes  an  exception  to  the  general  rule 
that  reciprocating  tools  are  not  used  in  woodworking 
machinery.  Aside  from  the  fact  that  it  is  one  of  the 
oldest  types  of  saw  used  in  this  connection,  the 
features  that  especially  commend  it  are  narrow  saw 
blades,  ability  to  cut  up  a  log  completely  in  one 
operation,  without  occasioning  loss  of  time  in  gig- 
ging, and  possibility  of  direct  connection  to  a  steam 
engine.  The  gang  saw  consists  of  a  heavy  vertical 
frame  in  which  a  saw-bearing  sash  slides  rapidly  up 
and  down.  A  number  of  parallel  saw  blades  are 
stretched  between  the  top  and  the  bottom  girts  of 
the  sash,  and  since  they  are  under  tension  only  they 
can  be  made  very  thin.  The  cut  is  taken  on  the  down 
stroke,  and  the  teeth  are  drawn  back  slightly  on  the 
up  stroke  in  order  that  they  may  not  drag;  this  back- 
ward motion  is  given  by  a  device  which  oscillates 
the  lower  end  of  the  sash,    Feed  rolls  (two  above  and 


WOOnWORKINCJ  MACHINERY 


423 


roll^  that  aro  (Mther  stationary,  as  shown  in  tho  ilhis- 
nation,  or  fastened  to  the  under  side  of  the  earria-e 
.irins-ers.  Bolted  to  it  are  a  number  of  head-blocks, 
1,  spliced  about  five  feet  apart,  which  support  the 
l(,o  on  its  under  side;  its  right-hand  side  rests  against 
tlM'  uprights,  i,  fastened  to  the  set  ))eani,  j.  The  log 
is  clamped  rigidly  to  the  uprights  by  hooks,  or 
-dogs,"  of  various  styles,  and  is  ^*set"  or  shifted 
across  the  carriage  by  the  handle,  k.  The  scale,  1, 
indicates  the  distance  between  the  upriglits  and  the 
saw.  The  foot  lever,  m,  brings  into  action  a  device 
tliat  'Miacks"  the  set  beam  to  take  on  a  new  log 
while  the  carriage  is  gigging. 

Gang  Saw.— The  gang  saw,  for  cutting  logs  into 
Uiniber,  constitutes  an  exception  to  the  general  rule 
that  reciprocating  tools  are  not  used  in  woodworking 
machinery.  Aside  from  the  fact  that  it  is  one  of  the 
()ld(»st  types  of  saw  used  in  this  connection,  the 
features  that  especially  conmumd  it  are  luirrow  saw 
hlades,  ability  to  cut  up  a  log  completely  in  one 
operation,  without  occasioning  loss  of  time  in  gig- 
ging, and  possibility  of  direct  connection  to  a  steam 
engine.  The  gang  saw  consists  of  a  heavy  vertical 
frame  in  which  a  saw-bearing  sash  slides  rapidly  u}) 
and  down.  A  number  of  parallel  saw  blades  are 
stretched  between  the  top  and  the  bottom  girts  oT 
the  sash,  and  since  they  are  under  tension  only  they 
can  be  made  verv  thin.  The  cut  is  taken  on  the  down 
stroke,  and  the  teeth  are  drawn  back  slightly  on  the 
up  stroke  in  order  that  they  may  not  drag;  this  back- 
ward motion  is  given  by  a  device  which  oscillates 
the  lower  end  of  the  sash.     Feed  rolls  (two  above  and 


424 


THE  MECHANICAL  EQUIPMENT 


WOODWORKING  MACHINERY 


425 


IH 


two  below  the  work)  carry  the  logs  through  the 
frame,  and  deliver  the  rough-cut  lumber  on  the  out- 
feeding  side. 

Power  Consumption  of  Saws.— The  power  consump- 
tion of  saws  varies  greatly  according  to  the  coarse- 
ness of  the  teeth,  width  and  depth  of  cut,  and  rate 
of  feed.  The  usual  cutting  speed  is  10,000  feet  a 
minute.  With  hand  feed  3  to  5  horsepower  is  re- 
quired. Heavy  power-fed  saw  benches  take  10  to  20 
horsepower,  and  feed  from  20  to  150  feet  a  minute; 
log  mills  require  25  to  50  horsepower,  and  the  feeds 
range  from  50  to  300  feet  a  minute. 

Planers,  Surfacers,  Moulders  and  Shapers.— On  ac- 
count of  vibration,  fast  cutting  speed  and  feed,  and 
the  fact  that  a  rip-saw  tooth  cuts  only  on  the  front 
and  tears  on  the  side,  all  rip-sawed  surfaces  must  be 
planed  by  being  passed  over  a  rapidly  revolving 
cylinder  carrying  two  or  more  thin  knives,  which 
make  a  series  of  light,  broad  cuts  as  nearly  parallel 
to  the  grain  as  possible.  The  knives  must  be  longer 
than  the  width  of  the  surface  to  be  planed,  and  the 
feed  and  the  cutting  speed  must  be  so  related  that 
no  visible  corrugations  will.be  produced.  Irregular 
surfaces  may  be  obtained  by  varying  the  contour  of 
the  knife-edges — in  every  case  the  surface  will  be  a 
counterpart  of  their  contour.  By  the  process  just 
described,  flooring  is  matched  and  beaded,  and  mould- 
ings are  made. 

The  hand  planer,  Figure  166,  consists  of  the  box 
frame,  a,  front  and  rear  carriages,  b  and  c,  front  and 
rear  tables,  d  and  e,  and  cutter-head  or  cylinder,  f. 
A  section  of  one  of  these  cylinders  in  a  somewhat 


FIG.  166.      HAND  PLANER 
H.  B.  Smith  Machine  Co. 


I    I 


FIG.  167.     SECTION  OF  A  SURFACER  HEAD 


424 


THE  MECIIANK  AL  EQrn>MI^:NT 


WOODWORK! N( I  AIACIILXERY 


425 


two    Ix'low    Uw    work)    carry    Uw    lo^s    tlir()u.t»']i    Ww 
frame,  and  (IHiv(>r  tlie  roii^i-ii-rut  limibcr  on  the  out 
feeding  side. 

Power  Consumption  of  Saws.— The  powiM-  eonsunip 
tion  of  saws  varies  greatly  aeeording  to  the  coarse 
ness  of  the  teeth,  widtli  and  (h'pth  of  eut,  and  7-at<' 
of  feed.  The  usual  cutting  speed  is  1(),()()()  feet  a 
minute.  With  hand  feed  .*)  to  o  horsepower  is  re 
quired.  Heavy  power-fed  saw  henches  take  10  to  2n 
horsepower,  and  fec^l  from  20  to  loO  feet  a  minute; 
log  mills  require  25  to  50  hors(7)()\\er,  and  the  feed> 
range  from  50  to  800  feet  a  minute. 

Planers,  Surfacers,  Moulders  and  Shapers.— On  ac- 
count of  vihration,  fast  cutting  spcM'd  and  feed,  and 
tlie  fact  tliat  a  rip-saw  tooth  cuts  only  on  the  front 
and  tears  on  the  sid(\  all  rip-sawed  surfaces  nmst  !).■ 
planed  by  being  passed  over  a  rapidly  revolving 
cylinder  carrying  two  or  mon^  thin  knives,  which 
make  a  series  of  light,  broad  cuts  as  nearly  parallel 
to  the  grain  as  possible.  The  knives  must  be  longer 
than  the  width  of  the  surface^  to  be  planed,  and  the 
r^ed  and  the  cutting  speed  nmst  l>e  so  relatc'd  thai 
no  visible  corrugations  will  be  ])roduc(Ml.  lrreii:ular 
surfaces  may  be  o])tained  by  varying  the  contour  of 
the  knife-edg(»s— in  every  case  the  surface  will  be  n 
counterpart  of  their  contour.  By  the  ])rocess  jus! 
described,  flooring  is  matched  and  l>eaded,  and  mould- 
ings are  made. 

The  hand  planer.  Figure  Kiti,  consists  of  the  l)o.v 
frame,  a,  front  and  rear  carriages,  b  and  c,  front  and 
rear  tables,  d  and  e,  and  cutter-head  or  cvlinder,  f. 
A   section   of  one  of  these   cylinders    in   a   somewha' 


Fl(i.    IGtJ.      HAND  PLANKR 
11.  ii.  yiiiiili  Macliiue  Co. 


FKl.  107.     SECTION  OF  A  SUKFACER  HEAD 


426 


THE  MECHANICAL  EQUIPMENT 


.WOODWORKING  MACHINERY 


427 


different  machine  is  shown  in  Figure  167.  Either 
table  may  be  raised  or  lowered  for  cuts  of  different 
thicknesses  by  a  turning  of  the  hand  wheel  g  or  h, 
as  the  case  may  be,  which  slides  it  over  inclines  on 
the  carriage.  The  adjustable  fence,  i,  acts  as  a  guide 
for  the  work;  the  bracket,  j,  which  is  ordinarily  re- 
moved or  swung  downward,  is  used  when  work  is  to 
be  rabbeted. 

It  was  customary  to  use  on  early  planers  a  cutter- 
head  of  rectangular  section,  with  a  knife  bolted  to 
each  face.  Necessarily  there  was  much  clearance 
between  head  and  table,  so  that  operators  frequently 
lost  some  of  their  fingers  in  feeding  the  tail  end  of  a 
board  over  the  knives.  Today  circular  cutter-heads 
with  inserted  knives  are  used  on  all  hand-feed  plan- 
ers, and  a  guard,  k  (Figure  166),  is  set  directly  over 
the  cutters. 

For  planing  long  boards  in  quantities  a  power  feed 
is  required.  The  cutter-head  is  mounted  on  an  ex- 
tension about  ten  inches  above  the  table.  Two  feed 
rolls,  also,  are  mounted  on  this  extension,  one  in 
front  of  the  cutter-head  and  the  other  behind  it.  The 
feeding-in  roll  is  fluted,  and  so  supported  as  to  have 
considerable  vertical  play  to  allow  for  unevenness  in 
the  rough  stock.  Directly  under  the  feed  rolls  are 
two  other  rolls,  which  work  through  slots  in  the 
table.  The  table  is  in  one  piece,  and  can  be  raised 
or  lowered  so  that  varying  thicknesses  of  stock  and 
depths  of  cut  can  be  obtained.  Front-  and  back-pres- 
sure bars— a  and  b.  Figure  167--hold  the  stock  firmly 
to  the  table  immediately  before  and  after  it  passes 
the  cutters.   A  machine  of  this  type  is  called  a  oingie- 


cvlinder  surfacer.  If  another  cutter-head  is  added, 
it  is  possible  to  surface  both  the  upper  and  the  lower 
side  of  a  board  at  the  same  time;  a  machine  that  has 
this  extra  cutter-head  is  called  a  double-cylinder  sur- 
facer. 

The  efficiency  of  these  machines  is  still  further  in- 
creased by  the  use  of  sectionalized  feeding-in  rolls 
and  pressure  bars,  each  section  being  pressed  down 
independently   by    a   weight    or   spring   device    (see 
Figure  167).    A  number  of  narrow  boards  which  are 
twisted,  or  whixih  have  slightly  different  thicknesses, 
can  then  be  fed  simultaneously,  and  the  full  width  of 
the  machine  can  be  utilized.  In  a  double-cylinder  sur- 
facer, the  upper  cutter-head  is  placed  ahead  of  the 
lower  one,  so  that  the  stock  has  a  firm  support  as 
it  passes  each  head.    The  table  can  be  raised  or  low- 
ered for  different  thicknesses  of  material  and  vary- 
ing cuts  of  the  upper  head;  while  the  lower  head,  car- 
ried  in  the  table,  can  be  raised  or  lowered  independ- 
ently  to  vary  the  cut  on  the  under  side  of  the  work. 
On  all  except  the  smallest  of  these  machines,  a  rapid 
adjustment  of  the  table-elevating  mechanism  can  be 

made  by  power. 

For  cutting .  mouldings,  hexagons,  full  and  sec- 
tional rounds,  and  other  strips  of  irregular  cross- 
section,  one  or  two  vertical  cutter-heads  are  desirable 
in  addition  to  the  horizontal  heads  of  the  surfacer. 
A  machine  that  has  these  additional  attachments  is 
called  a  moulder.  There  are  two  distinct  styles:  the 
outside  type,  in  which  the  table  is  supported  in  ver- 
tical slides  on  the  side  of  the  frame;  and  the  inside 
type,  in  which  the  table  is  supported  as  it  is  in  a 


428 


THE  MECHANICAL  EQUIPMENT 


r*' 


^1 


surfacer.  The  outside  moulder  is  not  rigid  enough 
to  be  used  for  wide  work,  but  it  is  more  accessible 
than  the  inside  moulder,  on  account  of  the  more 
open  construction.  In  both  types,  the  vertical,  or 
*' matcher,"  heads  have  vertical,  transverse,  and 
swiveling  adjustments,  and  the  feeding-out  rolls  are 
dispensed  with. 

Figure  168  shows  a  six-head  planer  or  matcher 
specially  adapted  for  finishing  boards  simultaneously 
on  all  sides,  and  used  in  the  manufacture  of  matched 
flooring.  The  lower  cutter  spindle,  a,  has  a  slight 
vertical  adjustment  to  compensate  for  wear  of  knives, 
while  the  upper  spindle  and  pressure  bars  can  be 
raised  and  lowered  on  the  guides,  b.  The  table  con- 
sists of  a  feeding-in  extension,  c,  with  adjustable 
fence  for  lining  up  the  rough  stock,  and  a  platen 
which  supports  the  work  under  the  top  cutter-head. 

On  some  machines  the  platen  and  the  lower  feed- 
ing-in rolls  have  a  wedge  adjustment  for  raising  and 
lowering  them  slightly,  so  that  the  thickness  of  the 
upper  and  the  lower  cuts  can  be  varied  without 
changing  the  thickness  of  the  finished  piece.  A  ma- 
chine of  this  type  is  said  to  have  a  'Svedge  platen.'' 
The  four  feeding-in  roll  centers  are  at  d,  and  the 
two  feeding-out  rolls  at  e.  These  rolls  give  a  positive 
feed,  and  yet  permit  a  wide  variation  in  the  thickness 
of  stock.  The  side,  or  matcher,  heads  are  located 
at  f.  In  the  illustration  one  of  the  driving  spindles 
may  be  seen  through  a  hole  in  the  frame  below;  the 
two  heads  at  the  left  end  are  used  for  beading  and 
for  other  narrow  cuts. 

The  power  consumption  of  machines  of  the  planer 


428 


TIIK  MKCHAXK'AI.  lOQllPxAIENT 


snrfacor.  Tlic  outsiile  moulder  is  not  rio'id  oiioiip^h 
to  ho  us(m1  for  wide  work,  hiil  it  is  more  accessible 
than  the  insich^  inonhhM-,  on  account  of  the  more 
open  construction.  In  hoth  tyjM's,  the  vertical,  or 
*'matclicr/'  heads  jiave  veitical,  transverse,  and 
swivelini;-  adjustments,  and  the  Feedino-out  rolls  arr 
disi)ensed  with. 

Figure    1()8    shows    a    six-liead    planer    or    matcher 
specially  adapted  for  linishini;-  hoards  siimdtaneously 
on  all  sides,  and  nsed  in  the  manufactui'e  of  matched 
flooring.     The    1ow(m-   cutter   spindle,   a,   has   a   slight 
vertical  adjustment  to  compensate  fo!'  wear  of  knives, 
while    the    upper   s])indle    and    pr(\<sure    hai-s    can    hr 
raised  and  lowen^l  on  the  guides,  h.     The  table  con- 
sists   of   a    feeding-in    extension,    c,    with    adjnstabl.' 
fence   for   lining   up   the    rough    stock,   and    a    platen 
which  supports  the  work  nnder  the  top  cutter-head. 
On  some  machines  the  platen  and   the  lower  feed- 
ing-in rolls  have  a  wedge  adjustment   for  raising  and 
lowering  them  slightly,  so  that  the  thickness  of  the 
upper    and    the    lower    cuts    can    be    varied    without 
changing  the  thickness  of  the  finished  piece.     A   ma- 
chine of  this  type   is  said  to  have  a  "wedg(.  platen." 
The   four   feeding-in    roll    centers   are    at    d,    and    the 
two  feeding-out  rolls  at  e.     These  rolls  give  a  positive 
feed,  and  yet  permit  a  wide  variation  in  the  thickness 
of    stock.      The   side,   or    matcher,    heads   are    located 
at  f.     In  the  illusti-ation  one  of  the  driving  spindles 
may  be  seen  through  a  hole  in  the  frame  Ixdow;  the 
two  heads  at    th<'  left   <'nd   are   us(»d   for  beading  arnl 
for  othei-  narrow  cuts. 

The  power  consumption  of  ma(diines  of  the  f)lane 


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430 


THE  MECHANICAL  EQUIPMENT 


WOODWORKING  MACHINERY 


431 


ill 


type  varies  with  the  feed,  width,  and  depth  of  cut, 
and  with  the  number  of  cutter-heads.  Hand  planers 
require  1  to  iy<^  horsepower,  single-cylinder  surfacers 
5  to  20,  double-cylinder  surfacers  15  to  25,  and  four- 
and  six-head  machines  up  to  40  horsepower.  These 
figures  are  for  the  usual  feeds  of  20  to  60  feet  a 
minute;  ** fast-feed ' '  machines,  with  feeds  up  to  250 
feet  a  minute,  require  up  to  60  horsepower.  The 
usual  cutting  speed  for  planers  is  5000  feet  a  minute. 

For  curved  work,  such  as  brush  backs,  and  handles 
for  hand  saws,  planes^  and  so  on,  a  vertical  spindle 
machine  with  hand  feed  is  desirable.  In  the  variety 
moulder  or  shaper.  Figure  169,  each  spindle  has  an 
independent  vertical  adjustment  for  varying  the 
height  of  the  cut,  and  can  be  depressed  entirely  below 
the  table  so  as  not  to  interfere  with  large  work. 
Ordinarily  the  shaper  has  a  solid  fixed  table;  but 
when  it  is  necessary  to  cut  profiles — such  as  column 
flutings — at  some  height  from  the  table,  the  front 
half  can  be  dropped,  as  shown,  and  the  work  can  be 
suppported  on  the  lower  level. 

Lathes. — For  general  manufacturing  the  lathe  is 
much  less  useful  than  the  planer  and  the  moulder; 
it  cannot  attain  the  high  cutting  speeds  of  the  planer 
without  causing  excessive  vibration  of  the  work,  and 
is  only  useful  for  producing  cylindrical  and  other 
surfaces,  of  revolution,  whereas  the  planers  and  the 
moulders  can  be  used  for  both  plane  and  cylindrical 
surfaces.  The  best  work  for  the  wood-turning  lathe 
is  pattern-making,  the  turning  of  table  legs,  stair 
balusters,  and  pieces  of  varying  diameter,  and  the 
manufacturing  of  elliptical   and   irregularly  curved 


FIG.  169.      DROP  TABLE  MOLDER 
S.  A.  Woods  Machine  Co. 

articles,  such  as  hammer  handles,  wagon-wheel  spokes, 
gun  stocks,  and  so  on. 

For  plain  turning,  a  light  ''speed  lathe"  is  used, 
with  bed,  legs,  headstock,  and  tailstock  like  those  ot 
an  engine  lathe.  No  back  gears  are  necessary,  for 
sufficient  speed  variation  is  obtained  by  means  of  a 
three-stepped  cone  pulley.  The  live  spindle  is 
threaded  to  receive  a  face  plate,  and  is  reamed  to 
take  a  three-pronged  spur  center  for  driving  long 
work  that  must  be  supported  at  both  ends.  The  tool 
is  usually  held  against  an  adjustable  rest  and  fed 


430 


THE  :\li:('lIAMC'AL  KQl  IPMENT 


WOUDWOKKIMJ   MACHINKIJV 


4:;i 


type  varies  with  tlie  feed,  width,  and  depth  of  cut, 
and  with  the  number  of  eutter-heads.  Hand  planers 
require  1  to  7 to  horsepower,  single-cylinder  surfacers 
')  to  20,  double-cylinder  surfacers  15  to  25,  and  foui- 
and  six-head  machines  up  to  40  horsej)ower.  Theso 
figures  are  for  the  usual  feeds  of  20  to  60  feet  a 
minut(»;  ^* fast-feed''  machines,  with  feeds  up  to  25(1 
feet  a  minute,  require  up  to  (iO  horsepower.  Tlio 
usual  cutting  speed  for  planers  is  5000  feet  a  minute. 

For  curved  work,  such  as  brush  backs,  and  handles 
for  hand  saws,  planes,  and  so  on,  a  vertical  spindle 
machine  with  hand  feed  is  desiral)le.  In  the  variety 
moulder  or  shaper,  Figure  169,  each  spindle  has  an 
independent  vertical  adjustment  for  varying  the 
height  of  the  cut,  and  can  be  depressed  entirely  below 
the  table  so  as  not  to  interfere  with  large  work. 
Ordinarily  the  shaper  has  a  solid  fixed  table;  l)ut 
when  it  is  necessary  to  cut  profiles — such  as  colunui 
flutings — at  some  height  from  the  table,  the  fi'oiit 
half  can  be  dropped,  as  shown,  and  the  work  can  be 
suppported   on   the  lower  level. 

Lathes. — For  general  manufacturing  the  lathe  is 
much  less  useful  than  the  planer  and  the  moulder; 
it  cannot  attain  the  high  cutting  speeds  of  the  planer 
without  causing  excessive  vibration  of  the  work,  an<l 
is  only  useful  for  producing  cylindrical  and  otluM- 
surfaces  of  revolution,  whereas  the  planers  and  th<' 
moulders  can  be  used  for  both  plane  and  cylindrical 
surfaces.  The  best  work  for  the  wood-turning  lath<' 
is  pattern-making,  the  turning  of  table  legs,  stair 
balusters,  and  pieces  of  varying  diameter,  and  th'' 
manufacturing   of   elliptical    and    irregularly    curved 


FU\.    IG9.      HKOP  TABLK   MOLHKli 
S.  A.  Wodds  MsH-hine  (\>. 

articles,  such  as  hammer  handles,  wagon-wheel  spokes, 
-un  stocks,  and  so  on. 

For  plain  turning,  a  light  ^'speed  lathe"  is  used, 
xvith  l)ed,  leo:s,  headstock,  and  tailstock  like  those  ol 
an  engine  lathe.  Xo  back  gears  are  necessary,  for 
snfiicient  speed  variation  is  ohtained  by  means  of  a 
lliree-stepped  cone  pulley.  The  live  spindle  is 
t breaded  to  receive  a  face  plate,  and  is  reamed  to 
take  a  three-pronged  spur  center  for  driving  Ion- 
work  that  must  be  supported  at  both  ends.  The  tool 
is   usuallv   held   against    an    adjustal>le    rest    and    U^d 


432 


THE  MECHANICAL  EQUIPMENT 


WOODWORKING  MACHINERY 


433 


m 


by  hand;  but  for  accurate  pattern  making,  tool  car- 
riages are  provided,  as  in  engine  lathes.  Face  lathes, 
consisting  of  a  headstock  mounted  on  a  suitable  base, 
with  tool  rest  carried  on  a  bracket,  are  used  for  turn- 
ing patterns  of  wheels,  pulleys,  cylinder  covers,  and 
the  like.  The  tools  commonly  used  for  these  lathes 
are  the  gouge  (for  roughing),  skew,  round-nose  and 
straight  chisels,  and  the  parting  tool. 

Gauge  Lathe. — The  gauge  lathe  is  used  for  turning 
table  legs  and  other  irregular  surfaces  of  revolution. 
The  irregular  contour  is  obtained  with  a  roughing 
tool,  which  follows  a  fixed  template,  or  former, 
secured  to  the  bed.  A  finishing  cut  is  taken  by  a 
formed  *'back  knife,"  mounted  obliquely  in  a  frame 
which  slides  in  two  vertical  guides  so  that  the  knife 
is  always  in  contact  with  the  work  just  behind  the 
roughing  tool.  If  the  former  is  rotated  at  the  same 
speed  as  that  of  the  work,  still  more  irregular  shapes 
can  be  turned,  which  need  not  be  surfaces  of  revolu- 
tion. 

Blanchard,  or  Copying,  Lathe.— Figure  170  shows 
a  Blanchard,  or  copying,  lathe,  used  for  turning  these 
irregular  forms.  The  essential  parts  are:  the  main 
frame,  shaped  roughly  like  that  of  a  speed  lathe;  and 
the  carriage,  a,  which  travels  on  the  ways  of  the  bed 
and  supports  a  revolving  cutter-head,  b.  A  vibrator 
frame,  c,  carries  a  former  or  pattern,  d,  revolving 
between  centers,  e,  e,  and  the  stock  (not  shown)  be- 
tween the  centers,  f,  f.  The  vibrator  is  supported  in 
bearings  in  the  lower  part  of  the  main  frame,  and  is 
oscillated  backward  and  forward  by  the  irregular 
pattern,  which  rotates  between  the  shoe,  g,  on  the 


FIG.  170.      BLANCHARD  OR  COPYING  LATHE 
J.  A.  Fay  &  Egan  Co. 

carriage,  and  the  shoe,  h,  on  a  pivoted  arm.  As  the 
stock  and  the  former  are  carried  in  the  oscillating 
frame  and  are  rotated  in  the  same  direction  and  at 
the  same  speed  by  means  of  the  drive,  i,  the  cutter- 
head  will  reproduce  in  the  work  the  shape  of  the 
pattern  above  it.  A  lead  screw  feeds  the  carriage 
along  the  bed  until  the  end  of  the  work  is  reached, 
when  the  pressure  of  the  shoes  is  automatically  re- 
leased and  the  carriage  is  returned  at  high  speed  to 
its  starting  position.  The  pattern  and  the  work  can 
be  rotated  between  fixed  centers  and  the  cutter-head 
and  shoe  can  be  carried  on  the  oscillating  frame;  this 


4:V2 


THE  MECHANICAL  EQUIPMENT 


!)>•  li;iri<l;  hut  Tor  accurate  pattorn  makiii.i;',  tool  eav 
riai^cs  arc  provided,  as  in  cn^'iiic  latlics.  Kacc  lathe,-, 
consist in.i;-  of  a  hcadstock  mounted  on  a  suitahle  has( . 
^vith  tool  I'cst  carried  on  a  hracket,  arc  used  for  turn 
mu;  patterns  of  wliecls,  pulk'vs,  cylinchM*  covers,  and 
the  like.     The  tools  coniinonlv   used   for  these  lather 

« 

are  the  gouge  (for  roughing),  skew,  round-nose  and 
straight  chisels,  and  the  parting  tool. 

Gauge  Lathe. — The  gauge  lathe  is  used  for  turnini' 
table  legs  and  other  iri'egular  surfaces  of  revolution. 
The  irregular  contour  is  obtained  with  a  roughini; 
tool,  which  follows  a  fixed  template,  or  forme!-, 
secured  to  the  bed.  A  finishing  cut  is  taken  by  a 
formed  *M)ack  knife,"  mounted  oblicpiely  in  a  frame 
which  slides  in  two  vertical  guides  so  that  the  knilV 
is  always  in  contact  with  the  work  just  behind  the 
roughing  tool.  If  the  former  is  i'otate<l  at  the  same 
speed  as  that  of  the  work,  still  more  irregular  shapes 
can  be  turned,  which  need  not  be  surfaces  of  revolii 
tion. 

Blanchard,  or  Copyings,  Lathe.— Figui-e  170  shows 
a  Blanchard,  or  copying,  lathe,  used  for  turning  thes<' 
irregular  forms.  The  essential  i)ai-ts  are:  the  main 
frame,  shaped  roughly  like  that  of  a  speed  lathe;  and 
the  carriage,  a,  which  travels  on  the  wavs  of  the  bed 
and  supports  a  revolving  cuttei'-head,  b.  A  vibrator 
frame,  c,  cai'ries  a  former  oi*  pattern,  d,  levolvinu 
between  centers,  e,  e,  and  the  stock  (not  shown)  be 
tweeii  the  centers,  f,  f.  The  vibrator  is  supjmrted  in 
bearings  in  the  lower  part  of  the  main  frame,  and  is 
oscillated  backwai'd  and  forward  bv  the  irresular 
pattern,    which    rotates    between    the   shoe,   g,   on  the 


WOODWOU'KINC    MAClliNKin" 


4.;:i 


no.    ITU.      BLANCllAKl)  OU   COPVINO   LATiiE 
.7.  A.  F;iy  &  Ejran  Co. 

cari'iage,  and  the  shoe,  h,  on  a  pivoted  arm.  As  the 
stock  and  the  former  are  carried  in  the  oscillating 
frame  an<l  are  rotated  in  the  same  direction  and  at 
the  same  s])eed  l)y  means  of  the  driv(\  i.  the  cutter- 
head  will  reproduce  in  the  work  the  shape  of  the 
pattern  a]>ove  it.  A  lead  screw  feeds  the  carriage 
along  the  bcnl  until  the  end  of  the  work  is  reached, 
when  tlie  pressure  of  tlie  shoes  is  automatically  re- 
leased and  the  carriage  is  returned  at  high  speed  to 
its  starting  ])osition.  The  pattern  and  the  work  can 
be  rotated  between  fixcul  centers  and  the  cutter-liead 
and  shoe  can  be  carried  on  the  oscillating  frame;  this 


HI' 
If.' 


434 


THE  MECHANICAL  EQUIPMENT 


arrangement  is  utilized  in  other  types  of  the  Blanchard 
lathe. 

MisceUaneous   Machines.-In   the   manufacture   of 
doors,  windows,  cars,  and  framed  articles,  the  borer 
and  the  mortiser  are  used  for  making  round  and 
rectangular  holes.   The  single-spindle  borer  resembles 
the  plain  drill  press  for  metal  drilling,  except  that 
a  hand  feed  is  always  used  and  the  table  usually  has 
a  universal   adjustment   for  positioning,   or   else  is 
fitted  with  rollers  for  handling  long  timbers.     The 
most  satisfactory  mortiser  is  the  hollow-chisel  type, 
illustrated  in  Figure  171.     The  cutting  tool,  a,  is  a 
square  hollow  chisel  which  trims  the  sides  of  the 
mortise,  inside  of  which  a  bit  rotates  and  clears  out 
the  material.    The  tool  is  fastened  to  the  plunger,,  b, 
which  has  a  power  feed  with  quick  return  and  an 
adjustable  travel  controlled  by  the  dogs,  c,  c.     The 
bit  spindle  is  carried  in  bearings  in  the  plunger,  and 
IS  driven  by  a  belt  passing  to  the  main  pulley,  e,  over 
the  idlers,  d,  d,  which  automatically  maintain  tension 
m  the  belt,  irrespective  of  the  position  of  the  spindle 
pulley  inside  the  plunger  head. 

The  carriage,  f,  in  which  the  plunger  slides,  has  a 
forward  adjustment  on  the  frame,  and  the  table,  g, 
has  vertical  and  longitudinal  adjustments,  all  oper- 
ated by  hand  wheels,  for  setting  the  work  and  vary- 
ing the  depth  of  mortise.  The  vise,  h,  is  specially 
designed  to  hold  down  the  work  while  the  chisel  is 
rising.  Unlike  the  old-style  mortisers,  which  were 
simply  machine-operated  chisels,  this  machine  fin- 
ishes the  hole  in  one  stroke  downward. 

The  wood-milling  machine  (P^ignre  172),  is  a  receiil 


>i 


4:^4 


Tin-;  MKCHAXK/AL  EQnPMKNT 


arrangement  i.s  utilized  in  other  types  of  the  Blanchar,] 
lathe. 

Miscellaneous   Machines.-!,,    the    manufaeture   r.f 
<loors,  window..,  ear.s,  and  framed  articles,  the  borer 
:ui<l    the   mortiser   are   used   for   making    round    and 
'■'■'•ta.|f,u!ar  holes.   The  single-spindle  borer  reseml.l,.. 
tlie  plain  drill  pres.s  for  metal  drilling,  except  thai 
a  luuid  feed  is  ahvay.s  used  and  the  table  usually  lia^ 
a    universal    adjustment    for   i)()sitioniiig,    or    else    i^ 
titted   with   rollers   for  handling  long  timbers.     Tlir 
most  satisfactory  mortiser  is  the  hollow-chisel   type 
Illustrated  in  Figure  171.     The  cutting  tool,  a,  is  a 
.'square   hollow   clii.sel   which   trims   the   sides   of   the 
mortise,  inside  of  which  a  bit  rotates  and  cleans  out 
the  mat.'rial.     The  tool  is  fastened  to  the  plunger,  1). 
which   ha.s  a   power  feed   with   quick   return   and   an 
adjustable  trayel   controlled   by   the  dog.s,  c,  e.     The 
l)it  spindle  is  carried  in  bearing.s  in  the  plunger,  and 
IS  driven  by  a  belt  pa.ssing  to  the  main  pulley,  e,  over 
the  Idlers.  <1.  d.  which  automatically  maintain  tension 
m  the  belt,  irrespective  of  the  position  of  the  spindle 
pulley  inside  the  plunger  head. 

The  carriage,  f.  in  which  the  plunger  slides,  has  a 
forward  adjustment  on  the  frame,  and   the  table,  jr. 
has  vertical   and  longitudinal   adjustment.s,  all   ope'r 
ated  by  hand  wheels,  for  setting  the  work  and  vary- 
ing the  depth  of  mortise.     The  vise,  h,  is  specially 
designed  to  hold  down  the  work  while  the  chisel  is 
rising.      Tnlike   the   old-style    mortisers,    which    were 
Miriply    machin.M.peral.'d    chisels,    (his    machine    fin 
ishes   (he   hole  in   one  stroke  downward. 
The  \v(i.M|-nii||ii|o  m.-icliiiic  (Kiginv  17l').  is  a  wrm' 


1  m 


436 


THE  MECHANICAL  EQUIPMENT 


WOODWORKING  MACHINERY 


437 


M*» 


« 


development  in  pattern-shop   equipment.      Like   the 
universal  miller  for  metal-working,  it  is  not  a  manu- 
facturing machine,  but  it  can  produce  an  almost  un- 
limited variety  of  shapes  with  the  accuracy  of  a  ma- 
chine tool.     It  corresponds  in  general  design  to  the 
vertical  die-sinker,  Figure  107.     The  spindle,  a,  is 
carried  by  a  head,  b,  at  the  end  of  an  adjustable 
counterbalanced  arm,  c;  the  head  swivels  90  degrees 
to   the   right  and  45   degrees   to   the  left,   and   the 
spindle  has  a  short  vertical  travel  independent  of  the 
arm,  controlled  by  the  hand  wheel,  d.    The  main  bed, 
e,  swivels  to  any  angle  desired,  and  supports  a  car- 
riage on  which  is  mounted  a  table,  f,  which  can  be 
swiveled  and  adjusted  transversely  or  longitudinally 
by  the  hand  wheels   shown.     Graduated   scales   are 
provided  for  facilitating  accurate  adjustments,   and 
the  carriage  can  be  fed  along  the  bed  by  either  hand 
or  power.     This  machine  is  very  useful  in  making 
core    boxes,    gear    patterns,    and    other    complicated 
shapes.     Other  wood  millers  are  constructed   along 
simpler  lines;  they  have  a  horizontal  and  a  vertical 
spmdle  mounted   directly  in   the   column,   with   the 
table  supported  in  a  knee  sliding  in  vertical  ways 
on  the  front  of  the  column. 

Sanding  machines  are  used  for  finishing  woodwork 
when  a  planed  or  a  turned  surface  is  not  sufficient. 
In  these,  the  cutting  element  consists  of  discs,  drums, 
or  cloth  belts  covered  with  sandpaper,  against  which 
the  work  is  held  until  ground  smooth  and  to  shape. 
Usually  the  work  rests  on  a  table  provided  for  the 
purpose,  and  is  fed  by  hand.  An  important  exception 
IS  the  multiple-drum  sander,  in  which  rotating  and 


oscillating  sanding  drums  polish  the  under  surface 
of  the  work  as  it  slides  along  the  table  under  the 
action  of  feed  rolls,  which  bear  down  on  its  upper 
surface. 


PAPER  MACHINERY 


439 


CHAPTER  XXIV 
PAPER    MACHINERY 

Rag  Machinery.— The  striking  characteristics  of 
paper  machinery  are:  large  power  consumption  in 
comparison  with  the  amount  of  labor  employed;  and 
the  use  of  water  and  steam  in  enormous  quantities, 
the  first  as  a  carrier  for  the  paper  fibres,  and  the 
second  for  cooking  and  drying.  Census  figures  show 
that  about  17  horsepower  per  wage-earner  is  con- 
sumed in  paper  and  pulp  manufacture;  in  steel  manu- 
facture and  rolling  only  about  half  that  amount  is 
used,  while  in  typical  machine  shops  only  2  or  3 
horsepower  per  wage-earner  is  employed.  The 
amount  of  water  used  is  indicated  by  the  fact  that 
for  every  ton  of  paper  produced,  from  12,000  to 
100,000  gallons  of  water  are  needed  for  such  processes 
as  washing  and  diluting,  in  addition  to  which  10,000 
to  15,000  gallons  must  be  used  in  the  form  of  steam. 

The  principal  machinery  and   apparatus  required 
in  the  manufacture  of  paper,  is  as  follows: 

For  converting  rags  into  **half  stock'*:  thresh- 
ers, rag-cutters,  dusters,  digesters,  washers. 

For  converting  wood  into  ''half  stock":  bark- 
ers, grinders,  chipping  machines,  digesters  for 
soda  or  sulphite  process. 

For  preparing  the  wet  pulp  or  ''stuff";  beat- 
ers, refiners. 

438 


For  making  machine-finished  paper:  Four- 
drinier  or  cylinder  machine,  including  winders 
and  one  or  more  calenders. 

For  cutting  and  finishing:  slitters,  cutters, 
super-calenders,  plating  and  glazing  rolls,  coat- 
ing machines. 

Auxiliary  apparatus:  belt  conveyors,  triplex 
and  centrifugal  pumps,  blowers,  exhausters,  and 

so  on. 
Dusters  and  Cutters.— The  purpose  of  rag  machin- 
ery is  twofold:  to  remove  loose  dust,  and  to  cut  the 
rags  into  small  pieces.    The  thresher,  which  performs 
the  first  of  these  duties,  consists  of  a  tightly  built 
wooden  chest,   about  eight  feet  high  and  ten  feet 
long,  with  a  side  door  through  which  the  rags  are 
charged;  a  wooden  cylinder  that  extends  lengthwise 
through  it,  is  provided  with  arms  or  beaters  project- 
ing radially  from  its  surface,  and  driven  by  a  pulley 
at  one  end  of  the  shaft.    The  cylinder  stirs  up,  pokes, 
and  pulls  out  the  lumpy  rags  as  they  come  from  the 
bale,  while  suction  ducts  connected  to  the  upper  part 
of  the  machine  draw  off  the  loose  dust.    The  "devil" 
works  on  the  same  principle;  its  shape  is  more  or 
less  cylindrical,  instead  of  rectangular,  and  the  re- 
volving beaters  are  aided  by  stationary  beaters  fixed 
on  the  inside  of  the  casing. 

There  are  two  types  of  duster.  In  the  railroad 
duster,  from  three  to  six  revolving  cylinders  are  set 
in  a  row,  each  covered  with  hard-wood  lagging,  and 
fitted  with  projecting  steel  pins  which  pass  between 
other  sets  of  pins  projecting  inwardly  from  the  cas- 
ing.   These  pins  beat  and  thresh  the  rags  as  they 


' 


'■  / 


IH 


440 


THE  MECHANICAL  EQUIPMENT 


no.  173.  TAYLOR  DUSTER       piG.  174.  RAG  CUTTER 

Holyoke  Machine  Co. 

travel  from  the  feeding  hopper  to  the  discharge  end 
of  the  machine,  while  the  dust  is  sucked  out  as  in 
the  case  of  the  thresher.    The  other  type,  illustrated 
by  the  Taylor  duster.  Figure  173,  is  of  about  the 
same  size  and  shape  as  a  thresher.    Inside  the  chest 
there  is  a  screen  consisting  of  one  or  two  skeleton 
cylinders,  covered  with  quarter-inch  mesh  wire  cloth 
rotated  by  the  pulley,  a;  there  is  also  a  central  shaft, 
fitted  with  propeller  blades  and  driven  in  the  oppo- 
site direction  by  the  pulley,  b.    The  rags  are  fed  into 
the  right-hand  end  of  the  screen,  and  as  they  are 
driven  through  to  the  left-hand  end  by  the  screw 
action    of   the    blades,   they   are    tossed    about    and 
dragged  over  the  screen,  being  thereby  freed  of  all 
remaining  loose  dirt,  buttons,  hooks,  and  so  on.    Ma- 
chines of  the  usual  size  can  handle  about  three  hun- 
dred pounds  of  rags  an  hour,  and  a  series  consisting 
of  one  thresher,  one  railroad  duster,  and  two  screen 
dusters,  will  remove  from  2  to  10  per  cent  of  the 
weight  of  the  stock  in  the  form  of  dust. 

Figure  174  shows  a  medium-sized  rag-cutter  for 
cutting  threshed  rags  into  strips  an  inch  or  less 
wide.     The  rags  are  fed  by  hand  or  by  a  belt  con- 


PAPER  MACHINERY 


441 


veyor  into  the  trough,  a,  passing  under  the  toothed 
feed-roll,  b,  to  a  series  of  revolving  knives  acting 
against  a  fixed  knife,  as  in  a  lawn  mower;    these 
knives  cut  them,  and  then  they  are  dropped  on  to  a 
discharging  conveyor  (not  shown  in  the  figure).    The 
driving  pulley,  c,  is  attached  directly  to  the  shaft 
carrying  the  knives,  the  feed  roll  being  driven  by  an 
open  belt  running  from  the  knife  shaft  to  pulley,  d, 
and  by  a  crossed  belt  from  pulley   e  to   pulley  f; 
these,  together  with  the  gearing  shown,  give  a  large 
reduction  in  speed.     The  feed  roll  does  not  run  m 
fixed  bearings,  but  rides  on  the  surface  of  the  rags, 
having  sufficient  weight  to  seize  them  with  its  teeth. 
Digesters  and  Washers.— The  digester  or  boiler  for 
saponifying  the  glutinous  and  resinous  substances  m 
rag  stock  and  washing  out  the  last  of  the  dust,  is  a 
spherical  or  cylindrical  steel  tank,  built  to  stand  forty 
to  fifty  pounds  of  pressure.    It  is  fitted  with  a  door 
for  charging  and  discharging  the  stock,  a  pipe  for 
supplying   steam,   another   for   letting   in   the   wash 
liquor,  and  one  or  more  blow-off  cocks.     It  may  be 
stationary  or  revolving;  in  the  former  case,  the  lower 
part  forms  a  reservoir  for  liquor,  above  which  is  a 
perforated  plate  on  which  the  stock  rests.    Steam  is 
admitted  at  the  bottom,  and  circulates  the  liquor  by 
blowing  it  up  through  a  central  pipe  to  a  spray-head 
near  the  top  of  the  boiler,  from  which  it  is  squirted 
down  over  the  rags,  somewhat  as  coffee  is  distributed 

in  a  percolator. 

Kevolving  boilers  are  supported  in  trunnions,  and 
are  rotated  slowly  by  worm  or  double-reduction  spur 
gearing.    One  trunnion  forms  an  inlet  for  steam,  the 


■\ 


440 


rilH  ME(  IIAMCAL  EQl'JPMENT 


PAPER  ^iAClIINERY 


441 


FIG.  173.   TAYLOR  DUSTER        FIG.  174.   RAG  CUTTF-R 

Ilolyoko  Macliino  Co. 

trnvcl  IVoni  tlio  tVodiii"-  lioppor  to  tlio  discliarov  ond 
of  the   inacliinc,   wliil,.  the  dust    is  sucked   out    as   in 
tho  case  of  tlie  tlnvslier.     Tlie  other  type,  illustrated 
l)y    the   Tayh)r   dust(M-,    Ki-ure    17;),    is   of   ahout    tli.' 
sauie  size  and  shape  as  a  thresher.     Iiisich'  the  ehesf 
there   is  a  screen   consisting  of  one  or  two   ske'.eton 
cylinders,  covered  with  (puirter-inch  niesli   wire  cloth 
rotated  hy  the  pulley,  a;  tlu^e  is  also  a  central  shaft, 
fitted   with  propeller  blades  and  driven   in   the  opjx) 
site  direction  hy  the  pulley,  h.     The  ra.os  are  \\h\  int.. 
the   rio-ht-hand   end   of  the   screen,   and   as   they   are 
driven    through    to    the   left-hand    end    hy    the    screw 
action    of    the    ])lades,    they    are    tossed    about    and 
dragged  over  the  scr(>en,  being  thereby  freed  of  all 
remaining  loose  dirt,  buttons,  hooks,  ami  so  on.     Ma 
chin(^s;  of  the  usual  size  can  handle  about  three  hun 
dred  pounds  of  rags  an  hour,  and  a  series  consisting 
of  one  thresher,  one  railroad  duster,  and  two  screen 
dusters,  will  remove  from   2  to   10  per  cent   of  th.' 
weight  of  the  stock  in  the  form  of  dust. 

Figure  174  shows  a  medium-sized  rag-cutter  foi 
cutting  threshed  rags  inlo  stri])s  an  inch  or  les.- 
wide.     The   rags  are  i'vd   by  hand  or  by  a  belt  con 


V,  vor  into  the  trougli,  a,  passing  under   the  toothed 
,,;.a-roll,    1),    to    a    series    of    revolving    kniv(>s    acting 
,..rmst    a    iixed    knife,   as    in    a    lawn    mower;    these 
knives  cut  them,  and  then  tliey  are  dn^nn'^l  ^>^i  ['^  '' 
ai-charging  conveyor  (not  sliown  in  the  figure).     1  he 
driving   pullev,   c,    is   attached   directly    to    the    shatt 
,arrviiig  the  knives,  the  feed  roll  l>eing  driven  l>y  an 
,,uvu  belt  running  from  the  knife  shaft  to  pulley,  d, 
.„ul    bv    a    crossed    belt    from    pulley    e    to    pulley    f; 
\\u'<v  'together  with  the  gearing  shown,  givi'  a  large 
,,duction   in   speed.     The  Uhh\   roll  do^'s   not   run   in 
fixed  bearings,  but   rides  on  the  surface  ot   the  rags, 
hnvin-  sufhcient  weight  to  seize  them  with   its  teeth. 
Digesters  and  Washers.— ^fhe  digester  or  boiler  lor 
saponifving  tlie  glutinous  and  resinous  substaiKvs  in 
rag  stock  and  washing  out  the  last  of  the  dust,  is  a 
s]»herical  or  cvlindrical  steel  tank,  ])uilt  to  stand  forty 
t(,  liftv  pounds  of  pressure.     It  is  titled  with  a  door 
for  cliarging  and  discharging  the   stock,   a   pipe  for 
sui)])lying    steam,    another    for    letting    in    the    wash 
liiiuor,  and  one  or  more   blow-off  cocks.      It   may    be 
stationary  or  revolving;  in  the  fornu'r  case,  the  lower 
part   fori'iis  a  reservoir  for  fupior,  above  which   is  a 
IK'rforated  plate  on  which  the  stock  rests.     Steam  is 
admitted  at  the  bottom,  and  circulates  tlu>  fKpior  by 
blowing  it  up  through  a  central  ])i])e  to  a  spray-head 
near  the  top  of  the  boiler,  from   which   it   is  s.iuirted 
(h)wn  over  the  rags,  somewhat  as  coffee  is  dislrilmted 

in  a  percolator. 

devolving  boilers  are  su])port'.Ml  in  trunnions,  and 
are  rotated  slowly  l)y  worm  or  double-reduction  spur 
gearing.     One  trunnion  forms  an  inlet  for  steam,  th- 


442 


I 


THE  MECHANICAL  EQUIPMENT 


PAPER  MACHINERY 


443 


Other  for  liquor.  The  capacities  of  these  boilers  vary 
from  2  to  6  tons  of  rags.  Spherical  ones,  which 
rarely  exceed  10  feet  in  diameter,  have  the  smallest 
capacity;  cylindrical  ones  range  in  size  up  to  25  feet 
in  length  and  10  feet  in  diameter,  and  hold  a  corre- 
spondingly greater  weight  of  stock.  The  steam 
pressure,  weight  of  liquor,  and  length  of  boil  vary 
according  to  the  chemicals  used  and  the  quality  of 
the  stock;  caustic  soda  requires  approximately  only 
half  the  pressure,  length  of  boil,  and  chemical  per 
pound  of  stock  that  caustic  lime  demands. 

A  washer,  or  Hollander,  as  it  is  frequently  called, 
because  of  its  invention  in  Holland,  is  used  for  re- 
moving the  dirt  and  coloring  matter  dissolved  from 
the  rags  in  the  digesters,  and  breaking  the  rags  up  into 
small  clumps  or  knots  of  fibre,  which  are  still  further 
subdivided  in  later  operations.  As  seen  in  Figure 
175,  the  washer  consists  of  an  oval-shaped  tub,  about 
20  feet  long,  9  feet  wide,  and  3  feet  high,  with  a 
partition  or  **midfeather''  dividing  it  into  two  parts 
for  two-thirds  of  its  length.  A  roll  faced  with  blunt 
steel  or  bronze  knives,  called  the  breaker  roll,  rotates 
in  one  part  under  the  semi-cylindrical  hood,  and  one 
or  more  wash  drums  (not  visible  in  the  illustration) 
covered  with  wire  cloth,  rotate  in  the  other  part. 
Both  roll  and  drums  have  their  bearings  adjustable 
in  vertical  slides,  so  that  their  depth  of  immersion 
can  be  varied. 

The  floor  of  the  tub  is  smooth  and  level,  except 
in  three  places:  the  *' breast,"  directly  in  front  of  the 
breaker  roll,  where  it  slopes  up  slightly;  under  the 
roll,  where  it  supports  a  plate  carrying  6  or  8  knives 


FIG.  175.      WASHER 

E.  D.  Jones  &  Sons  Co. 

like  those  on  the  roll;  and  behind  the  roll,  where  it 
rises  in  a  curve  close  to  the  circumference  of  the  roll, 
and  then  slopes  down  to  its  normal  level — the  ' '  back- 
fall," as  it  is  termed.  In  operation,  the  washer  is 
filled  with  boiled  rag  stock  and  water,  and  the 
breaker  roll  paddles  the  mixture  over  the  back-fall 
to  the  wash  drums  and  back  again  for  two  to  six 
hours.  The  fibres  are  torn  apart  and  brushed  length- 
wise—not cut-— as  they  pass  between  the  knives  of 
the  roll  and  floor  plate,  which  are  brought  closer 
together  as  the  stock  becomes  more  subdivided;  at 
the  same  time,  dirty  water  escapes  to  the  interior 
of  the  wash  drum,  from  which  it  is  withdrawn 
through  one  of  the  bearings  either  by  dippers  or  by  a 
siphon. 


442 


TIIK  MECHAXICAL  Ki^l  ll\\[Ki\T 


otlier  for  liciiior.  Tlie  capacities  of  tliosc  ])oil(M-s  var\ 
from  2  to  (i  tons  oi*  ra^s.  Splicrical  ones,  wliicli 
rarely  exceed  10  feet  in  diameter,  Iiave  tlie  smaller 
capacity;  cylindrical  ones  range  in  size  np  to  2')  IVhI 
in  length  and  JO  feet  in  diameter,  and  liold  a  coitc 
spondingly  greater  weight  of  stock.  The  steam 
pressnre,  weight  of  liqnor,  and  length  of  boil  vary 
according  to  the  chemicals  used  and  the  quality  of 
the  stock;  caustic  soda  requires  approximately  only 
half  the  pressure,  length  of  boil,  and  clnMuical  pei- 
pound  of  stock  that  caustic  lime  demands. 

A  washer,  or  Hollander,  as  it  is  frequently  called, 
because  of  its  invention  in  Holland,  is  used  foi-  re- 
moving the  dirt  and  coloring  matter  dissolved  from 
the  rags  in  the  digesters,  and  breaking  the  rags  up  into 
small  clumps  or  knots  of  fibre,  which  are  still  furthci- 
subdivided  in  later  operations.  As  seen  in  Figure 
175,  the  washer  consists  of  an  oval-sha])ed  tub,  al)oiil 
20  feet  long,  9  feet  wide,  and  '^  feet  high,  with  a 
partition  or  *'midfeather"  dividing  it  into  two  parts 
for  two-thirds  of  its  length.  A  roll  faced  with  blunt 
steel  or  bronze  knives,  called  the  breaker  roll,  rotatt^s 
in  one  part  under  the  semi-cylindrical  hood,  and  one 
or  more  wash  drums  (not  visible  in  the  illustration) 
covered  with  wire  cloth,  rotate  in  the  other  part. 
Both  roll  and  drums  have  their  bearings  adjustabl*' 
in  vertical  slides,  so  that  their  depth  of  immersion 
can  be  varied. 

The   floor  of  the  tub   is  smooth   and   level,   excejit 
in  three  places:  the  **breast,''  directly  in  front  of  the 
breaker  roll,  where  it  slopes  up  slightly;  under  tli- 
roll,  where  it  supports  a  plate  carrying  G  or  8  kni\  <  - 


PAPER  MA(  HINERY 


44:j 


FIG.   175.      WASHER 
B.  I).  Jones  &  Sons  Co. 

like  those  on  the  roll;  and  Lehind  the  roll,  where  it 
lises  in  a  curve  close  to  the  circumference  of  the  roll, 
and  tlicn  ^]()\h^^  down  to  its  normal  level— the  ''back- 
fall," as  it  is  termed.  In  operation,  the  washer  is 
lill.Ml  with  boiled  rag  stock  and  water,  and  the 
bivak<'r  roll  paddles  tlie  niixture  over  the  back-fall 
to  the  wash  drums  and  back  again  for  two  to  six 
iiours.  The  libres  are  torn  apart  and  brushed  length- 
^vis('— not  cut — as  they  pass  between  the  knives  of 
tlie  roll  and  floor  plate,  which  are  1)rought  closer 
together  as  the  stock  becomes  more  subdivided;  at 
the  same  time,  dirty  water  esca])es  to  the  interior 
'.'M  the  wash  drum,  from  which  it  is  withdrawn 
through  one  of  the  l)earings  either  by  dippers  or  by  a 
siphon. 


444 


THE  MECHANICAL  EQUIPMENT 


PAPER  MACHINERY 


445 


' 


Wood-Pulp   Machinery.— Wood   pulp   is   of    three 
principal  kinds:  mechanical,  soda,  and  sulphite,  each 
of   which    requires    special    machinery.      Mechanical 
pulp,   which  is  simply  finely  ground  wood  fibre,  is 
made  in  a  grinder,  an  example  of  which  is  shown  in 
Figure  176.     This  is  an  emery  or  sandstone  wheel 
rotating  on  a  horizontal  shaft  within  the  casing,  a. 
Three  or  more  pockets,  b,  with  doors,  are  built  into 
the  casing,  over  each  of  which  is  mounted  a  hydraulic 
cylinder,  c,  whose  plunger  moves  radially  in  relation 
to  the  wheel.    The  logs  to  be  ground  are  cut  into  two- 
foot  lengths,  barked  in  machines   (described  in  the 
next  paragraph),  split  into  boards,  and  freed  as  far 
as  possible  from  knots.    These  boards  are  then  set  in 
the  pockets  and  pressed  by  the  plunger  against  the 
rotating  stone,  which  slowly  wears  them  away.     A 
stream  of  water  keeps  the  wood  from  burning,  and 
at  the  same  time  washes  away  the  pulp  which  varies 
greatly  in  quality  according  to  the  amount  of  water 
used.    As  can  be  imagined,  the  friction  of  these  ma- 
chines consumes  a  great  quantity  of  power;  for  ex- 
ample, a  6-pocket  grinder  with  a  wheel  whose  sur- 
face  speed  is   3000   feet   per  minute,   requires   1200 
horsepower. 

Barkers  and  chippers  are  required  for  preparing 
logs  for  the  soda  and  sulphite  processes.  These 
machines  differ  with  respect  to  the  method  of  feeding 
the  logs.  In  both  cases,  knives  are  mounted  on  the 
face  of  an  inclosed  disc,  about  5  feet  in  diameter, 
rotating  on  a  horizontal  shaft.  The  casing  with  its 
discharge  spout  for  bark  and  chips,  has  the  appear- 
ance of  a  centrifugal  pump.    The  barker  has  a  device 


FIG.  176.   WOOD  PULP  GRINDER 
The  Bagley  &  Sewall  Co. 

m 

on  one  side  which  holds  the  logs  (cut  to  short  length, 
as  in  the  mechanical  pulp  process)  in  a  horizontal 
position  and  forces  them  against  the  knives,  rolling 
them  over  at  the  same  time  until  the  bark  is  com^ 
pletely  sheared  off.  The  chipper  has  an  inclined 
chute,  through  which  the  logs  are  fed  end  on;  in  this 
case,   the   knives  break   them  up  into   small   chips 


444 


TIIK   MKCIIANirAI,   K(,)|  ||\MKi\T 


M^ 


Wood-Piilp    Machinery.^ Wood    |)iilp    is    of    tlm 
prin('i|)nl   kiiuis:  niecliimicnl,  soda,  niid  sul|)liit(\  oadi 
of    wliich     r(M|uir(>s    special    inacliinci-y.       Mrclianic.il 
]>ulp,    wliicli    is    siiii|>ly    lincly    .i;i-oi']id    wood    lihr(»,    is 
made  ifi  a  i^i'iiidci',  an  ('xanij)l('  ol    wliicli   is  shown  in 
r'i.U'urc    1<(>.      11iis    is   an    cnicr'v    or   sandstone    wlicc] 
rolalin.u-  on   a   liorizonial   slial'l    witliin   tlic  casini*-,  a. 
TliriM'  or  moi'c  ])o('I<('ls,   h,   willi   doors,  ai'c   huilt   inlo 
lilt'  casin.i;",  ovim*  each  of  which  is  nionntcd  a  liydi'anlic 
cylindiM',  c,  whose  ])lnn.i;'er  moves  i-adially  in  i-elatiori 
to  the  wheel.     The  h).i;s  to  be  ^ronnd  ai'e  cnt  into  two- 
loot    lengths,    i)arked    in    machines    (described    in    the 
next    para,urai)h),  split    into   hoai'ds,  and    ['vinnl  as   far 
as  ])ossil)le  from  knots.     These  hoai'ds  ai-e  then  set  in 
the  po<'kets  and   ])i-esse(l    hy   the   plnnitcr  against   tlic 
rotating-   stone,    wliicli    slowlv    weai-s    them    awav.      A 
stream   of   water   kee])s   the   wood    from   ])ni-nin,i;-,   and 
at  the  same  time  washes  away  tlie  ])n]p  which  varies 
.areatly  in  (piality  according-  to  tlie  amonnt   of  wat-r 
used.     As  can  he  ima<iine(l,  the  friction  ol*  these  ma- 
chines consnmes  a  .u'reat   (plant ity  of  ])ower;   for  ex- 
ample, a   (i-pocket    i»i'inder   with    a    wheel    whose  sur- 
face   ^]UH'i]    is    :U)00    feet    per    minute,    recpiin^s    ]2(H) 
horsepow  ci". 

IJarkei's  and  cliippers  are  rerpiired  for  ])i-epari]i,L: 
lo.iis  for  the  soda  and  sulphite  processes.  'I'hesf 
machines  <liffer  with  respect  to  the  nietliod  of  feedin- 
the  lous.  Fn  both  cases,  knives  are  mounted  on  t1i<' 
face  of  an  inclosed  disc,  about  5  feet  in  (liamet<'r, 
rotating-  on  a  horizontal  shaft.  The  casino-  with  ils 
dischai'Kc  spout  for  bai'k  and  chips,  has  the  a])pear- 
ance  of  a  centrifugal  i)ump.     The  barker  has  ii  devi 


IfC 


PAIMHi  MAf  nii\i:RY 


445 


FIG.  17G.    WOOD  I'TLP  (IRIXDER 
The  Hairley  .V:  Sew  nil  < '.i. 

on  one  side  wliicli  holds  tlie  logs  (cut  to  short  length, 
as  in  the  mechanical  l)ul])  ])rocess)  in  a  liorizontal 
position  anil  foi'ces  them  against  th<'  knives,  rolling 
them  over  at  the  sanu'  time  until  the  hai-k  is  com- 
plet(dy  sheared  off.  The  chipp(M'  has  an  inclined 
•'hute,  through  which  the  logs  are  fed  end  on;  in  this 
<'ase,    the    knives    l)reak    them    up    into    ifmail    chips 


/ 


■*;l 


f  ■ 


446 


THE  MECHANICAL  EQUIPMENT 


with  an  action  which  corresponds  to  the  blow  of  an 
axe  in  felling  a  tree. 

The  digesters  for  soda  pulp  are  like  those  used 
for  rag  stock.  The  capacities  are  much  greater,  how- 
ever, and  the  ste"^m  pressure  higher;  20  tons  of  chips 
are  a  usual  charge,  and  require  8  to  10  hours  boil- 
ing at  a  100-pound  pressure.  The  sulphite  pulp- 
digester  must  be  lined  with  lead,  brick,  or  cement, 
because  of  the  corrosive  sulphurous  acid  that  the 
liquor  contains.  It  is  built  vertically,  about  8  feet 
in  diameter  and  45  feet  high,  and  is  arranged  either 
to  admit  steam  directly  to  the  liquor  at  an  80-pound 
pressure  for  the  rapid  process,  or  to  circulate  the 
steam  through  pipe  coils  at  a  45-pound  pressure  for 
the  slow  process.  The  sulphite  digester  requires 
ovens  for  burning  sulphur  with  a  deficient  supply  of 
air.  The  acid  calcium  sulphite  solution  is  formed 
in  wooden  towers  charged  with  broken  limestone 
which  is  converted  by  a  current  of  sulphur  dioxide, 
led  in  at  the  base,  and  a  counter-current  of  w^ter 
sprayed  down  from  the  top. 

A  series  of  riffles,  or  **sand  traps,''  followed  by 
strainers  removes  knots  and  pieces  of  undigested 
wood  from  the  '^half-stuff"  produced  in  the  digest- 
ers. The  stuff  is  then  pumped  to  the  beaters  cr,  if 
it  is  to  be  shipped  to  another  mill,  is  concentrated 
and  made  into  soft,  thick  sheets  of  ** air-dry"  pulp. 
The  *'slusher,"  used  for  the  concentrating,  is  a 
wooden  vat  with  a  partition  dividing  it  into  a  large 
and  a  small  part;  a  cylinder  covered  with  wire  clotli 
rotates  in  the  large  part,  picks  up  a  coating  of  fibre 
from  the  dilute  stuff  which  surrounds  it,  and  trans- 


PAPER  MACHINERY 


447 


fers  this  fibre  to  a  felt-covered  roll,  from  which  it  is 
scraped  into  the  small  compartment  of  the  vat  hold- 
ing the  concentrated  material. 

Beaters  and  Refiners.— The  half  stock  and  the  air- 
dry  pulp  are  mixed  in  the  proper  proportions  and 
prepared  for  the  paper  machine  in  a  beater,  the  func- 
tion of  which  is  to  separate  the  fibres  and  draw  them 
out  to  their  extreme  length  without  cutting  them. 
This  machine  is  like  the.  washer  for  rag  stock,  pre- 
viously described;  the  chief  differences  are  the  finer 
vertical  adjustment  of  the  beater  roll,  the  omission 
of  wash  drums,  and  the  grouping  of  the  roll  knives 
in  sets  of  three  or  more  with  wide  space  between 
the  sets  to  make  the  roll  more  efficient  as  a  paddle 
wheel  for  the  stuff,  which  is  much  more  dilute  than 
in  the  washer.  Sharp  knives  are  used  to  produce 
*'free"  or  *'fast"  stock  suitable  for  filter,  duplicat- 
ting,  blotting,  and  news-print  papers;  medium  blunt 
knives  for  turning  out  high-grade  writing  and  print 
paper,  and  very  blunt  ones  for  the  production  of 
bond,  strong  wrappings,  and  so  on,  requiring 
** greasy"  stock.  In  the  latter  case,  stone  floor  plates 
opposite  the  knives  are  sometimes  used. 

The  capacities  of  the  beaters  vary  widely.  Medium 
sizes  are  about  16  feet  long,  8  feet  wide,  and  3  feet 
deep,  with  a  roll  31/2  feet  in  diameter,  and  hold  the 
equivalent  of  500  pounds  of  air-dry  pulp;  the  largest 
sizes  hold  from  2000  to  3000  pounds.  In  all  cases, 
the  circumferential  speed  of  the  roll  is  about  2000 
feet  a  minute.  The  power  consumption  per  ton  of 
stuff  diminishes  as  the  size  of  beater  increases;  it 
also  varies  greatly  with  the  clearance  between  roll 


V 


448 


THE  MECHANICAL  EQUIPMENT 


m 


and  bed  plate,  and  with  rate  of  circulation  of  the 
stuff,  21/2  horsepower  per  100  pounds  of  dry  stuff 
being  a  fair  average. 

The  operation  of  refining  or  brushing  out  the  fibres 
straight  and  parallel,  may  be  performed  on  the  beater 
by  raising  the  roll  shortly  before  emptying.     In  the 
case  of  high-grade  paper,  however,  this  operation  is 
done  in  a  Jordan  or  Marshall  refiner,  which  consists 
ot  a  conical  drum  carrying  longitudinal  beater  knives 
revolving  mside  a  conical  shell,  with  corresponding 
knives  set  on  its  inner  surface.     The  clearance  be- 
tween stationary  and  rotating  knives,  varied  by  slid- 
ing  the  drum  longitudinally,  is  just  sufficient  to  give 
the  desired  brushing  action  to  the  fibres  as  the  stuff 
flows  through  from  the  small  to  the  large  end  of  the 
cone. 

Paper  Machines.-By  far  the  greatest  tonnage  of 
paper  is  produced  on  the  Fourdrinier  machine,  in- 
vented and  patented  by  a  French  paper-maker,  Louis 
Robert,  m  1799,  and  perfected  some  years  later  by 
Henry  and  Sealy  Fourdrinier,  the  proprietors  of  an 
English  paper  mill.  The  machine  has  undergone  no 
fundamental  changes,  but  has  been  improved  in  de- 
tails to  increase  the  size,  speed,  flexibility  of  drive 
recovery  of  stock  from  the  waste  water,  and  safety 
ot  the  operators. 

A  typical  machine  is  shown  in  elevation  in  Figure 
177,  and  m  plan  in  Figure  178.     It  consists  of  a 

wet  end,  on  which  the  paper  is  formed,  two  or 
three  pairs  of  press  rolls,  which  reduce  it  to  the  cor- 
rect thickness,  a  series  of  drying  rolls,  one  to  six 
stacks  of  calenders,  and  one  or  more  reels  on  which 


PAPER  MACHINERY 


449 


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450 


THE  MECHANICAL  EQUIPMENT 


PAPER  MACHINERY 


451 


the  machine-finished  paper  is  wound.  The  pulp  flows 
from  the  beaters  to  the  stuff  chests,  a  and  b. 
Figure  178,  where  it  is  kept  from  settling  by  paddles 
attached  to  vertical  rotating  shafts.  It  is  then 
pumped  to  a  regulating  box  (not  shown),  in  which 
it  is  diluted  to  its  final  •  consistency  and  maintained 
at  a  constant  level  by  means  of  an  overflow  pipe, 
which  assures  a  constant  flow  into  the  machine. 
From  here  it  passes  through  a  regulating  cock  to  the 
sand  tables,  a  series  of  long,  narrow,  inclined  troughs 
covered  on  the  bottom  with  long-haired  felt  or  with 
strips  of  wood  set  at  45  degrees,  which  catch  any 
coarse  solid  particles,  as  well  as  sand  and  dirt  that 
have  not  yet  been  separated  from  the  fibre.  The 
lower  end  of  these  sand  tables  appears  at  c. 

The  pulp  then  flows  to  the  strainers,  d,  d,  to  re- 
move knots  and  intertwined  fibres.  The  usual  type 
of  strainer  has  a  flat  plate,  about  7  feet  long  and  21/2 
feet  wide,  pierced  with  fine  slits  2  to  3  inches  long, 
a  quarter-inch  apart,  and  less  than  0.05  inch  wide, 
which  allow  only  individual  fibres  to  pass  through. 
In  order  that  the  action  may  be  more  rapid,  the  plate 
is  jogged  up  and  down  by  a  crank  and  pitman,  or 
else  a  vibrating  diaphragm  in  the  trough  under  the 
plate  produces  an  alternating  puffing  and  suction 
action.  Other  types  of  strainers  have  revolving  or 
oscillating  cylinders  instead  of  flat  plates. 

The  pulp  that  fails  to  pass  the  strainers,  d,d,  is 
washed  off  to  the  auxiliary  strainer,  e,  and  all  that 
passes  this  one  is  returned  to  the  regulating  boxes 
for  dilution  with  fresh  stuff.  That  which  passes  the 
main  strainer  is  led  directly  to  the  '*wire"  of  the 


452 


THE  MECHANICAL  EQUIPMENT 


machine.  This  is  an  endless  sheet  of  wire  cloth,  f 
(Figures  177  and  178);  30  to  50  feet  long  and  100  to 
250  inches  wide,  woven  with  about  70  strands  per 
inch,  and  passing  from  the  breast  roll,  g,  to  the  lower 
couch  roll,  h,  and  back  again.  On  its  forward  travel 
it  is  supported  by  a  number  of  small  rolls,  i,  set  close 
together,  returning  over  and  under  the  rolls  j,  whose 
position  can  be  adjusted  so  that  they  will  regulate 
the  tension  of  the  wire. 

The  stuff  is  fed  to  the  wire  on  an  apron  of  rubber 
or  waterproof  cloth,  k,  whose  edges  are  folded  up  to 
keep  the  pulp  from  overflowing,  and  is  spread  evenly 
to  the  proper  thickness  by   an   adjustable   gate,  or 
** slice,"  at  the  point  where  it  flows  from  the  apron 
onto  the  wire.     It  is  carried  along  by  the  wire,  re- 
strained on  either  side  by  the  endless  rubber  bands, 
1,1,  called  deckle  straps,  while  the  water  collecting 
in  the  meshes  of  the  wire  is  carried  off  on  the  sur- 
face   of    the    rolls    by    capillary    action    and    passes 
into   the   troughs,   m,m.     Just   before   reaching   the 
couch  rolls,  the  wire  runs  over  suction  boxes,  n,n, 
where  a  large  amount  of  water  is  taken  from  the 
pulp   by  vacuum   pumps.     This,    together   with   the 
water  from  the  troughs  m,  m,  and  from  the  strainer, 
e,  drains  into  the  low-box,  y,  from  which  it  is  pumped 
to  the  high-box,  z,  for  dilution  with  fresh  pulp. 

The  watermark,  if  one  is  desired,  is  produced  be- 
tween the  suction  boxes  by  a  light  wire  skeleton 
cylinder  called  a  ^Mandy  roll,''  having  the  pattern 
in  raised  wires  on  its  surface  which  rests  on  the  sur- 
face of  the  paper.  From  the  breast  roll  to  the  first 
suction  box,  the  wire,  the  deckle  straps,  and  the  sup- 


PAPER  MACHINERY 


453 


porting  rolls  are  all  carried  on  the  deckle  frame,  o, 
which  is  hinged  at  the  left-hand  end  to  a  fixed  part  of 
the  machine  and  is  given  a  rapid  sidewise  *' shake'' 
at  the  right-hand  end,  with  the  object  of  thoroughly 
interlacing  the  fibres  as  they  are  formed  into  a  web 
of  paper.  This  action  is  the  essential  characteristic 
of  the  Fourdrinier  machine. 

The  moist  paper  leaves  the  wire  at  the  couch  rolls, 
and  is  immediately  picked  up  by  an  endless  sheet  of 
felt,  p,  which  carries  it  through  the  first  press  rolls, 
q,  q,  after  which  it  is  turned  over  and  picked  up  by 
another  felt,  r,  and  carried  through  the  second  press 
rolls,  s,  s.  Thus  each  side  of  the  paper  comes  into 
direct  contact  with  a  roll  and  is  smoothed  by  it. 
From  this  point  the  web  passes  up  and  down  over 
steam-heated  drying  rolls,  t,  from  sixteen  to  forty 
in  number,  being  held  in  close  contact  by  the  felts 
shown  in  the  figure.  The  pair  of  steam-heated 
smoothing  rolls,  u,u,  of  polished  chilled  iron,  give 
the  paper  a  preliminary  calendering.  The  machine  is 
often  arranged  for  sizing  by  interposing  between  two 
batteries  of  dryers  a  tank  of  sizing  material  into 
which  the  paper  is  passed. 

The  calender,  v,  at  the  left  of  the  dryers,  puts  the 
*^ machine  finish"  on  the  web  of  paper.  Pressure  is 
applied  by  screws  or  by  weights  and  levers;  the 
paper  passes  progressively  between  each  roll  and 
the  next  lower  one,  and  under  the  combined  action 
of  pressure  and  steam  heat  is  compressed  and  given 
a  smooth,  hard  surface.  Any  number  of  calenders 
may  be  installed  in  series,  the  number  depending 
upon  the  grade  of  finish  desired.    The  web  is  finally 


454  THE  MECHANICAL  EQUIPMENT 

trimmed  on  the  edges  and  slit  to  the  desired  widths 
by  rotating  disc  knives,  w;  then  it  is  wound  on  the 
reel,  x. 

Figure   178   shows   a   typical   power  drive   for   a 
Fourdrimer  machine.     The  shake,  couch  roll,  press 
ro  Is,  first  and  second  drying  batteries,   smoothers, 
calender,  and  reel,  are  driven  separately  from  the 
mam   shaft    by   the    cone   pulleys    and    bevel    gears 
showii  m  the  figure;  thus  is  secured  the  independent 
speed  regulation  necessary  for  counteracting  irreg- 
ularities in  the  shrinkage  of  the  paper  as  it  dries, 
ihe  power  consumption  of  medium-sized  machines 
from  breast  roll  to  reel  with  the  driving  mechanism, 
is  about  8  horsepower  per  ton  of  paper  per  24  hours 
To  this  figure  must  be  added  50  per  cent  for  stuff- 
pumps,  strainers,  and  other  auxiliaries.   The  tendency 
IS  to  make  wider  machines;  whereas  150  inches  was 
about  the  maximum  a  few  years  ago,  wires  over  200 
inches  wide  are  in  operation  today.  At  the  same  time 
speeds  have  increased;  at  present  a  wire  speed  of  250 
feet  a  minute  is  a  fair  average,  and  700  feet  is  the 
upper  limit,  though  that  will  doubtless  be  exceeded 
m  the  near  future.     These  wide,  fast  machines  re- 
quire much  more  power  than  the  amount  mentioned 
above. 

A  modified  form  of  Fourdrinier,  known  as  the 
single-cylinder  machine,  is  sometimes  used  for  very 
thin  paper,  or  paper  to  be  finished  on  one  side  only. 
The  distinguishing  feature  is  a  single  drying  cylinder 
about  10  feet  in  diameter,  in  the  place  of  the  battery 
of  smaller  cylinders,  t,  on  the  Fourdrinier.  A  ma- 
chine which  is  similar  in  name,  but  entirely  different 


PAPER  MACHINERY 


455 


i 


mmrmmmmmmmm}mMiimnf}W)im\ 


FIG.  179.     CYLINDER  PAPER  MACHINE 

in  form— called  a  cylinder  machine— is  used  for  the 
manufacture  of  low-grade  paper,  mill  board,  and  air- 
dry  wood  pulp.  The  strained  pulp  enters  a  tank,  a. 
Figure  179,  in  which  a  skeleton  cylinder,  b,  covered 
with  wire  cloth,  revolves.  The  fibres  stick  to  the 
wire  while  the  water  passes  through  the  meshes, 
under  the  action  of  a  suction  pump;  the  sheet  of 
paper  thus  formed  is  removed  from  the  cylinder  at 
the  couch  roll,  c,  by  the  felt,  d,  which  carries  it  to 
the  large  steam-drying  roll,  e.  After  drying,  it  is 
wound  off  on  the  reel,  f;  the  felt  in  the  meantime 
returns  to  the  couch  roll  through  the  washer,  g,  over 
the  scraper,  h,  and  between  the  squeezing  rolls  or 

wringers,  i,  i. 

One  cylinder  cannot  make  a  thick  sheet,  so  that  in 
the  manufacture  of  heavy  paper  board  a  number  of 
cylinders  are  mounted  in  tandem,  the  wet  webs  being 
taken  off  in  successive  layers  on  the  same  felt;  it  is 
thus  possible  to  obtain  different  colors  on  opposite 


456 


THE  MECHANICAL  EQUIPMENT 


PAPER  MACHINERY 


457 


FIG.  180.     SUPERCALENDER 
Holyoke  Machine  Co. 

sides  of  the  same  sheet.  In  a  modification  of  this 
machine,  the  drying  cylinder,  e,  is  replaced  by  a  pair 
of  press  rolls,  and  the  wet  web  is  wound  on  the  upper 
roll  until  the  required  thickness  has  been  obtained, 
when  It  IS  slit  across  from  side  to  side,  taken  from 
the  rolls,  laid  out  flat,  and  dried  in  heated  lofts. 

Finishing  Machinery.— A  super-calender  is  used  for 
obtaining  a  smoother  surface  than  that  which  is 
called  '* machine  finish.''  A  typical  machine  of  this 
kind  is  shown  in  Figure  180,  which,  with  the  omission 


of  the  winding  device,  would  represent  an  ordinary 
calender.  The  rolls  are  built  up  in  stacks  of  four  to 
twelve,  compressed  paper  rolls  alternating  with 
chilled  iron.  Pressure  is  applied  by  means  of  levers 
and  tension  rods,  a,  connected  to  weights.  A  reel  of 
dampened  paper  is  placed  at  b,  and  the  paper  is  fed 
over  the  guide  rolls,  c,  to  the  top  calender  roll,  and 
then  back  and  forth  between  the  rolls  until  it  reaches 
the  bottom;  finally  it  is  rewound  at  d.  The  drive  is 
through  the  shaft,  e,  to  the  lowest  roll,  which  can  be 
driven  directly  or  at  a  lower  speed  through  back 
gears.  The  unwinding  reel  is  held  back  by  the  brake, 
f,  which  keeps  a  uniform  tension  in  the  paper;  and  the 
winding  reel,  belt-driven  from  g,  can  be  slowed  down 
any  desired  degree  as  the  roll  of  paper  increases  in 
diameter. 

In  contrast  with  this  variable-speed  reel,  the  con- 
stant-speed winder.  Figs.  177  and  178,  should  be  noted. 
In  this  case  the  power  is  applied  to  the  rolls,  a',  b',  in- 
stead of  to  the  reel,  and  since  the  paper  travels  at 
constant  speed,  the  reel,  which  simply  rests  on  the 
rolls,  will  be  rotated  at  the  right  speed  whatever 
the  amount  of  paper  wound  upon  it.  In  order  that 
the  paper  may  be  wound  tightly,  b'  is  driven  slightly 
faster  than  a'. 

For  plate  glazing  or  linen  finishing  a  special  two- 
roll  calender  is  used  which  is  provided  with  hori- 
zontal front  and  back  tables  level  with  the  top  of  the 
lower  roll,  and  a  reversing  drive  is  employed.  A 
stack  of  paper  sheets,  alternating  with  copper  or  zinc 
plates  or  sheets  of  linen,  is  set  on  the  front  table  and 
passed  back  and  forth  between  the  rolls  until  the 


Mi 


456 


THE  MECHANICAL  EQUIPMENT 


FIG.  180.     SUPERCALKXDER 
Ilolyoko  Machine  Co. 

sides  of  the  same  sheet.  In  a  modification  of  thi> 
maehiTHs  tlie  dryino.  cyVuulrv.  c,  is  rephieed  hv  a  ikdi 
of  press  rolls,  and  tln^  uvt  wcl,  is  wound  on  tile  upprr 
n)ll  uiitd  the  recpiired  thickness  has  hcen  obtaincl. 
wlien  It  is  slit  across  from  si<lc  to  side,  taken  from 
the  rolls,  laid  out  flat,  and  dried  in  heated  lofts. 

Finishing- Machinery.— A  super-calender  is  used  f.M 
o])tainino-  a  smoother  surface  than  that  whicli  i< 
^'^'"^•^^  'Mnachine  linish.''  A  typical  machine  of  tln< 
kind  IS  shown  in  Figure  180,  which,  with  th(i  omission 


PAPEK  MACHIXEHV 


4; 


')t 


of  the  windin.i;'  device,  wouhl  rcprcsrnt  an  <)r<linai"y 
calender.  The  rolls  are  built  n\)  in  stacks  of  foui*  to 
iwelve,  compressed  paper  rolls  altei-natint;-  with 
cliilled  iron.  Pressure  is  ap[)lied  l)y  means  of  levers 
jiiid  tension  rods,  a,  connectiMl  to  weights.  A  reel  of 
dampened  paper  is  placed  at  I),  and  the  pajjei*  is  fed 
over  the  guide  rolls,  c,  to  the  top  calendei*  I'oll,  and 
tlieii  hack  and  forth  between  the  rolls  until  it  reaches 
I  lie  bottom;  linallv  it  is  rewound  at  d.  The  drive  is 
llirougli  the  shaft,  e,  to  the  lowest  roll,  which  can  l)e 
driven  directly  or  at  a  lower  s})eed  through  back 
iiears.  The  unwinding  I'eel  is  held  back  bv  the  bi-ake, 
r,  wliicli  keej)s  a  uniform  tension  in  the  ])aper;  and  the 
winding  reel,  belt-driven  fi'om  g,  can  be  slowed  down 
any  desired  degree  as  the  roll  of  pa])er  increases  in 
diameter. 

In  contrast  witli  this  variable-si3eed  reel,  the  con- 
slant-speed  winder,  Figs.  177  and  178,  should  be  noted. 
In  this  case  the  power  is  applied  to  the  rolls,  a',  b',  in- 
stead of  to  the  reel,  and  since  the  paper  travels  at 
constant  speed,  the  reel,  which  simply  rests  on  the 
rolls,  will  be  rotated  at  the  right  speed  whatever 
the  amount  of  i^aper  wound  upon  it.  In  order  that 
the  paper  may  be  w^ound  tightly,  b'  is  driven  slightly 
faster  than  a'. 

For  plate  glazing  or  linen  finishing  a  special  two- 
roll  calender  is  used  whicli  is  pi'ovided  with  hori- 
zontal front  and  hack  taldes  level  with  the  top  of  the 
lower  roll,  and  a  reversing  drive  is  em])l()yed.  A 
stack  of  paper  sheets,  alternating  with  c()i)per  or  zinc 
plates  or  sheets  of  linen,  is  set  on  the  front  table  and 
passed    ])ack    and    forth    between    the    rolls    until    the 


458 


THE  MECHANICAL  EQUIPMENT 


surfaces  are  sufficiently  finished.  Friction  glazing  is 
done  on  a  two-  or  three-roll  calender  in  which  one  of 
the  rolls  is  driven  much  faster  than  the  others  by  a 
special  spur-and-pinion  connection. 

The  most  highly  finished  paper  is  made  by  coating 
with  a  mixture  of  china  clay  and  thin  glue.     The 
apparatus  for  this  process  varies  in  details,  but  al- 
ways has  these  principal  parts:  a  vat  for  holding 
the  coating  fluid;  brushes  for  working  out  lumps  and 
smoothing  the  coated  surface;  an  automatic  carrier 
for  conveying  the  coated  paper  through  the  drying 
room;   and  glazing   calenders.     The   body  paper  is 
passed  through  the  vat,  between  two  press  rolls  which 
remove  the  excess   coating,   and   then   between   tw6 
sets  of  brushes,  one  above   and   one  below,   which 
vibrate  across  the  paper.     Each   set  consists  of  a 
coarse,  a  medium,  and  a  fine  brush— the  last  usually 
camel's  hair— working  in  series  on  the  web  of  paper. 
After  leaving  the  last  brushes,  the  web  is  picked  up 
at  intervals  of  fifteen  to  twenty  feet  by  cross  bars, 
which  rise  toward  the  ceiling  and  then  travel  hori- 
zontally into  the  drying  room.     The  web,  therefore, 
hangs  in  festoons  reaching  nearly  to  the  floor,  and  is 
dried   without  touching  anything  except   the   cross 
bars.  After  drying  the  web  is  reeled  and  run  through 
calenders  that  polish  the  surface. 


CHAPTER  XXV 
BOOT  AND  SHOE  MACHINERY 

General  Characteristics. — The  machines  used  in 
making  boots  and  shoes  are  quite  unlike  those  which 
are  to  be  found  in  other  lines  of  manufacture.  The 
difference  is  due  to  the  nature  of  the  principal  mate- 
rial used,  to  the  small  size  of  the  parts  composing  the 
shoe,  and  to  the  kinds  of  operation  performed.  In 
general,  shoe  machines  translate  into  mechanical 
processes  the  manual  dexterity  of  the  old-fashioned 
shoemaker  in  using  the  hammer,  knife,  awl,  and 
needle.  The  fundamental  machines,  most  of  them  de- 
veloped by  clever  shoemakers,  were  original  in  de- 
sign, and  even  those  now  used  for  pressing,  rolling, 
grinding  and  buffing  are  distinctive,  for  they  do  not 
closely  resemble  the  corresponding  machinery  in 
wood  or  metal-working,  although  they  perform  the 

same  operations. 

History  of  Shoe  Machinery.— The  first  important 
shoe  machine,  which  was  invented  in  1815,  made 
wooden  pegs  for  fastening  the  soles  of  shoes  to  the 
uppers.  In  1845  the  rolling  machine  was  introduced, 
for  compressing  and  hardening  sole  leather;  this 
mechanical  process  replaced  the  hand  hammering 
which  had  been  in  vogue  up  to  that  time.  In  1851 
a  Lynn  shoemaker,  by  the  name  of  Nichols,  adopted 

450 


'im 


i 


I 


460  THE  MECHANICAL  EQUIPMENT 

Howe's  sewing  machine  to  sewing  shoe  uppers,  and 
a  year  later  the  machine  was  used  in  the  manufacture 
of  shoes  by  John  Wooldredge,  also  of  Lynn.     The 
introduction  of  this  machine  made  shoe  manufacture 
distinctly   a   factory   industry.     In    1858   Lyman   R 
Blake,  another  shoemaker,  invented  a  machine  for 
sewing  uppers  and   soles  together,  which   was  im- 
proved by  Mathies  and  built  by  Gordon  McKay,  a 
capitalist  and  manufacturer.    It  was  first  used  com- 
mercially in  1861,  and  now  the  name  McKay  is  given 
to  one  of  the  most  widely  manufactured  types  of 
shoe  in  this  countrv. 

A  still  more  important  advance  was  made  in  1862, 
when  Aiiguste  Destouy,  a  New  York  mechanic,  in- 
vented a  machine  with  a  curved  needle  for  sewing 
the  soles  of  turn  shoes.     This  was  developed  under 
the  direction   of  Charles   Goodyear,   son  of  the  in- 
ventor of  the  vulcanizing  process,  and  in  1875  was 
applied  to  the  sewing  of  welts  to  insoles  in  the  manu- 
facture of  *' Goodyear  welt''  shoes,  which  are  superior 
to  all  other  tvpes  in  comfort,  wearing  quality,  and 
appearance.    The  manufacture  of  the  rougher  grades 
was  made  materially  easier  by  the  commercial  appli- 
cation, in   1857,  of  a  pegging  machine  for   driving 
the  wooden  pegs  that  hold  together  the  insole,  upper, 
and  outsole  in  pegged  shoes. 

The  first  successful  lasting  machine,  the  invention 
of  c  Boston  lawyer,  George  Copeland,  was  exhibited 
at  the  Centennial  Exposition,  in  1876.  A  machine 
duplicating  the  hand  method  of  lasting  was  invented 
in  1883  by  Matzeliger,  an  expert  machinist  who  came 
to  Lynn  from  Dutch  Guiana  and  learned  the  shoe 


BOOT  AND  SHOE  MACHINERY 


461 


trade.  These  two  machines  eliminated  the  only  re- 
maining hand  process  in  shoe  manufacture:  that  of 
stretching  the  upper  over  the  last  and  securing  it 
temporarily  by  nails,  until  the  sole  was  attached. 
These  machines  have  been  supplemented  by  the  puU- 
ing-over  machine,  which  prepares  the  shoe  for  last- 
ing. A  recent  invention  is  the  clicking  machine,  for 
cutting  uppers  from  the  hide  or  skin;  it  takes  the 
place  of  the  workman  with  his  patterns  and  knife, 
who  was  known  as  the  hand  cutter. 

Machine  Operations. — The  principal  operations 
performed  in  shoe  manufacture  are:  cutting,  bend- 
ing and  stretching,  and  stitching.  Among  the  ma- 
chines for  the  first  of  these  operations  are  clicking 
machines,  stripping  machines  for  cutting  hides  into 
strips  of  a  width  equal  to  the  length  of  the  sole,  sole- 
cutting  or  **dieing-out"  machines,  splitting  machines, 
channelers,  skiving  machines,  edge  setters,  and  so  on. 
Some  of  these  work  on  the  principle  of  the  punch, 
others  use  either  rotary  or  stationary  knives,  while 
still  others  use  revolving  cutters  similar  to  milling  cut- 
ters. Some  of  the  machines  for  the  second  class  .of 
operations  are  sole-laying  and  sole-leveling  machines 
for  bending  the  sole  to  the  proper  shape,  channel- 
opening  and  channel-laying  machines  for  raising  and 
flattening  the  channels  on  insoles,  and  pulling-over 
and  lasting  machines  for  stretching  the  uppers  over 
the  lasts.  The  third  group  is  made  up  of  sewing 
machines  of  different  types,  some  of  which— such  as 
the  McKay  sewing  machine,  the  Goodyear  welt,  and 
the  Goodyear  outsole  rapid-lockstitch  machine — stand 
as  landmarks  in  the  development  of  shoe  machinery. 


7 


i 


462 


THE  MECHANICAL  EQUIPMENT 


Other  operations  performed  by  special  machines  are 
rollmg,  hammering,  pressing,  nailing,  cementing,  iron- 
ing, grinding,  buffing  and  polishing. 

Arrangement  of  a  Shoe  Factory.— The  modern  shoe 
factory  is  composed  of  six  departments:  for  cutting, 
stitching,  stock  fitting,  ** making''  or  bottoming,  finish- 
ing and  treeing,  and  for  packing  and  shipping.  The 
cutting  and  stitching  rooms  are  usually  on  the  top 
floor,  and  the  sole  leather  room  is  generally  on  the 
ground  floor.  The  bottoming  room  is  on  the  floor  next 
below  the  cutting  and  stitching  departments,  and  the 
shipping  room  is  generally  on  the  floor  next  above 
the  sole-leather  room. 

Types  of  Shoes.— The  methods  now  in  use  for  fas- 
tening the  upper  to  the  sole  are:  (a)  McKay,  (b) 
Goodyear  welt,  (c)  Turned,  (d)  Standard  screw,  (e) 
Pegged. 

Figure  181  shows  these  methods.     In  the  McKay 
sewed  shoe  method,  a,  the  upper  and  the  lining  are 
held  m  the  insole  by  a  row  of  tacks  driven  from  the 
outsole  side  and  clinched  at  the  points;  the  outsole 
IS  .then  stitched  on  using  a  single  thread  and  chain 
stitch,  the  channel  being  opened  up  during  the  stitch- 
mg  and  closed  or  ^^aid''  after  the  stitching  is  com- 
pleted.    Sometimes   an   additional   seam,   known   as 
''fair  stitching,''  is  run  around  the  outsole  close  to 
the  edge  in  imitation  of  the  Goodyear  welt.     This 
method  is  comparatively  cheap,  but  leaves  a  row  of 
nail  points  and  a  seam  of  heavy  thread  inside  the 
shoe;  moreover,  when  it  is  used  it  is  also  impossible 
to  put  on  a  new  outsole  without  sewing  through  to 
the  inside— a  stitch  difficult  to  make  by  hand. 


BOOT  AND  SHOE  MACHINERY 


463 


McKay  Stam 


Uppe> 


•Inseam 


Weft 


i         Outsole 
Channel        Filling  <Channel 

<a>   McKAY  SHOE 


Channel    Filling  "Oufsole     ''(^fseam 
(b>   GOODYEAR   WELT  SHOE 


/      \5urface  Channel 
Seam  (Open) 


Channel  (Laid }       ''Sole 


LASTED  AND  SEWED  BEFORE  TURHIM6  THE  SAME  AFTER  IT  HAS  BEEN  TURNED 

<C>    TURN  SHOE 

"         yUpper 

.'Lining 


Cd)    STANDARD  SCREW  SHOE 


■"Peg 


(e>  PEGGED  SHOE 


FIG.  181.     TYPES  OF  SOLE  FASTENINGS 

The  Goodyear  welt  derives  its  name  from  the  strip 
or  welt  of  leather  which  runs  around  the  outsole 
between  the  upper  and  the  edge  of  the  sole,  uniting 
the  insole,  upper  leather  and  outsole  by  the  two  rows 
of  stitching  shown  in  the  figure.     Although  appa- 


A 


464 


THE  MECHANICAL  EQUIPMENT 


rently  complicated,  the  processes  of  this  method  are 
easily  carried  out  by  machinery,  and  they  produce 
the  most  comfortable  and  durable  type  of  shoe. 
Furthermore  the  outsoles  can  be  easily  repaired 
either  by  hand  or  by  machine. 

Turn  shoes,  e,  are  sewed  together  inside  out;  the 
stitch  used  IS  similar  to  the  inseam  stitch  of  a  welt 
Shoe.  The  shoe  is  then  turned  right  side  out  and  the 
final  operations  of  heeling,  and  so  on,  are  performed 
upon  It  as  in  the  case  of  other  shoes.  Turn  shoes 
are  very  light  and  flexible,  and  the  inner  surface 
ot  the  sole  IS  smooth  and  free  from  nail  points  or 
seams  of  thread.  This  type  of  shoe  is  used  for  sli«. 
pers,  pumps,  and  ladies' fine  footwear 

Standard  screw  and  pegged  shoes  resemble  the 
McKay  type,  in  that  tacks  are  used  for  attaching 
the  upper  leather  to  the  insole;  in  the  McKay  shoe, 
however,  the  outsole  is  fastened  on  by  threaded  wire 
screws,  while  in  the  pegged  type  pegs  of  calendered 

wl  .r°fl  ^ZT^-  '^'  standard-screw  shoes,  which 
lack  the  flexibility  of  sewn  soles,  are  used  for  heavy, 
rough  wear.     Nailed   shoes   are   similar   to  pegged 

r'lono?.*  *^^*  "^^'^  ^''  substituted  for  the  pegs. 

In  1909  the  relative  production  of  these  different 
types  in  the  United  States  was  McKay,  41.5  per  cent; 
Goodyear  welt,  32.3  per  cent;  turned,  16.3  per  cent 
standard  screw,  7.9  per  cent;  pegged  and  nailed,  2 
per  cent.  ' 

Cutting  Room  Machinery—The  essential  parts  of 
the  clicking  machine  (see  Figure  182)  are  a  frame 
carrying  a  cutting  block,  a,  consisting  of  maple 
boards  set  with  the  grain  end  on;  a  vertical  plunger, 


4G4 


THE  MECHANrCAL  EQUIPMENT 


rent  y  oon.pl.cato.l,  tlio  pro(.oss,.s  „f  tl,is  „i..tI,o<l  aro 
oa.ily  ,arno.l   ,.ut    l.y   ,„a.-l,in,.ry    an.l   Ihov   pro,],,.-. 
!.<■    n.o.t    <-o.Mf..rtal.h.    a.ul    .lural.l,.    tvpo'of     .l.o. 
JMirthennoro,    tl.e    outsolos    ,.„.    h.    oasily    repaired 
t'ltlier  by  hand  or  ))y  maeliiiu.. 

Turn  slices,  <•,  arc  sow.mI  toffether  inside  out;  tlio 
s  .t<-l,  used  IS  si.uilar  to  tl>e  insean.  slitel,  of  a  welt 
|;lH.e.  Il.e  shoe  is  then  turned  right  side  out  and  the 
<'"al  operations  of  heeling.  an<l  so  on.  are  pcM-forn.e.l 
"po..  .t  as  ,n  the  ease  of  other  shoos.  Turn  shoes 
a.e   very   l,g|,t   and    flexil.le.  and    the    inner   surfaee 

1.  '"  7  ','  "  r"""*''  ■■'""'   ^''''  <■'■«'"  """  points  0'- 
seams  ot  thread.     This  type  of  shoe  is  used  for  slit,- 

pt'rs.  pumps,  and  ladies'  fine  footwear 

Stan<lar.l    serew    an.l    pegged    shoes    resemble    the 
AleKay   type,   in   that    taeks   are   us..l   for   attaching 
''<•  upper  leather  to  the  insole;  in  the  MeKav  shoe, 
I'owever,    he  outsole  is  fastened  on  bv  thread.:,!  wire 
«-.-ews.  wlMle  in  the  pegged  type  pegs  of  eale„dere,l 
beeehwood  are  used.    The  standard-screw  shoes,  which 
lack  the  flexibility  of  sewn  soles,  are  used  for  heavy, 
rough    wear.      Kailed    shoes    are    similar    to    pegged 
shoes    except  that  nails  are  substituted  for  the  pegs 
In   ]!)()!)  the  relative  pro.luction  of  these  different 
.ypcs  m  the  United  States  was  :VlcKay,  41.5  per  cent; 
f.oo.lyear  welt,  32.3  per  cent;  turned.  l(i.3  per  cent 
staiKlard  screw,  7.!)  per  cent;  peggvd  an.l   naih.l,  2 
per  cent.  ' 

Cutting  Room  Machinery.-The  essential  parts  of 
the  clicking  machine  (.see  Figure  182)  are  a  frame 
carrying  a  cutting  block,  a,  consisting  of  maple 
boards  set  with  the  grain  end  on;  a  vertical  plunger, 


'A 


'.1 


7\ 


2 
EH 


IT 

o 


466 


THE  MECHANICAL  EQUIPMENT 


BOOT  AND  SHOE  MACHINERY 


467 


d;  and  an  arm,  c,  attached  to  the  plunger,  which  rises 
and  falls  with  it  and  may  be  swung  so  as  to  cover 
any  part  of  the  cutting  block.  The  operator  places 
a  skin  on  the  block,  sets  a  light  steel  die  or  ring, 
about  three-quarters  of  an  inch  thick  and  sharpened 
on  one  edge,  on  that  portion  of  the  skin  which  he 
wishes  to  cut  out,  swings  the  arm  over  it,  and  then 
forces  the  die  through  the  leather  and  a  slight  dis- 
tance into  the  wooden  block.  It  might  seem  that  the 
continued  forcing  of  sharp  dies  into  the  cutting 
block  would  roughen  it  and  soon  spoil  the  surface. 
This  is  not  the  case,  for  the  fibres  become  spongy 
and  elastic  because  the  surface  of  the  block  is  kept 
well  oiled.  This  method  of  cutting  against  an  elastic 
surface  is  characteristic  of  leather  manufacture. 

The  cutting  of  cloth  linings  is  done  in  a  similar 
way,  but  "dieingr-ouf  machines  replace  the  pressure 
arm  of  the  clicking  machine  with  a  strong  beam 
operated  by  means  of  eccentrics  from  a  driving  shaft 
below.  The  larger  sizes  have  cutting  blocks  96  inches 
long,  16  inches  wide,  and  10  inches  high,  and  are 
capable  of  cutting  fifty  thicknesses  of  lining  at  a 
stroke.  Clicking  machines  do  not  require  such  stroncr 
construction,  since  the  operator  cuts  only  one  thick- 
,  ness  of  leather  owing  to  the  fact  that  he  must  select 
the  best  parts  of  each  skin  and  place  his  dies  to  leave 
a  minimum  amount  of  scrap. 

The  skiving  machine  bevels  or  scarfs  the  upper 
leather  to  a  thin  edge,  after  which  cement  is  applied 
to  the  beveled  surface  and  the  edge  is  folded  back 
upon  itself  and  pressed  into  place  so  that  nothing 
but  the  grain  side  shows.     The  Amazeen  machine, 


Figure  183,  has  a  feeding  device,  made  up  of  a 
knurled  roll,  a,  and  a  smooth  disk,  b,  at  right  angles 
to  it  and  forced  against  the  upper  surface  of  the  feed 
roll  by  a  helical  spring,  c.  An  adjustable  guide,  d, 
holds  the  right-hand  edge  of  the  leather  at  the  proper 
point  as  it  passes  backward  between  the  feed  roll 
and  the  feed  disk;  a  rotary  disk-knife,  set  directly 
back  of  the  feed  on  an  inclined  shaft,  e,  can  be  ad- 
justed for  various  amounts  of  bevel;  and  a  grinding 
wheel,  f,  mounted  behind  the  knife,  can  be  brought 
into  action  so  as  to  grind  the  knife  without  removing 
it  from  the  machine.  For  heavier  work  machines  are 
used  which  are  similar  to  this  except  that  they  have 
a  stationary  knife. 

The  skived  edges  are  cemented  on  the  top  of  a  box- 
shaped  bench  machine.  This  has  a  small  metal  wheel 
with  roughened  surface  projecting  through  a  slot  in 
the  top  which  supplies  the  cement  to  the  work.  The 
inside  of  the  machine  is  a  cement  reservoir,  the  ad- 
hesive being  fed  by  a  screw  pump  to  a  well  under 
the  wheel,  which  overflows  at  a  fixed  level  so  that  the 
wheel  cannot  be  flooded. 

After  being  cemented,  the  edges  are  turned  or 
folded  on  a  machine  of  which  there  are  two  types. 
In  the  "Boston,'*  the  leather  is  laid  on  the  table  of 
the  machine  and  is  gripped  along  its  entire  length, 
about  a  half-inch  from  the  edge,  between  two  clamps 
that  have  the  same  curve  as  this  edge;  a  block,  also 
shaped  to  this  curve,  rises  past  the  clamps  and  then 
approaches  them,  thus  folding  the  edge  back  upon 
itself  The  ''Columbia"  machine  folds  and  hammers 
down*  a  short  length  of  the  edge,  and  then  feeds  the 


468 


THE  MECHANICAL  EQUIPMENT 


BOOT  AND  SHOE  MACHINERY 


469 


work  a  distance  equal  to  the  length  folded  over.  This 
machine  is  slower  than  the  Boston,  but  does  not  re- 
quire special  clamps  and  blocks  for  each  shape  of 

Stitching.Room  Machinery.-Uppers  and  linings  are 
stitched  on  sewing  machines  which  are  adaptations 
of  the  sewing  machine  for  cloth.    The  essentials  are 
the  frame,  the  feed,  and  the  stitching  mechanism. 
A  C-trame  is  used,  at  the  upper  end  of  which  is  the 
mechamsm  for  moving  the  needle  up  and  down,  whil- 
the  lower  end  forms  the  table  on  which  the  work  is 
laid.    This  table  may  be  flat  and  flush  with  the  bench, 
for  sewing  flat  work;  or  it  may  be  convex  and  sup- 
ported 3  to  6  inches  above  the  bench  on  a  vertical 
post  or  a  horizontal  cylinder  which  is  part  of  the 
trame.     The  principal  feeds  are  the  ** four-motion'' 
and   the   -rotary."     The  four-motion   consists   of  a 
serrated  plate  set  in  a  slot  in  the  table,  which  rises 
to  the  work,  draws  it  backward  the  length  of  one 
stitch,  descends,  and  returns  to  its  first  position;  the 
rotary  is  a  wheel  with  a  serrated  edge,  which  is  in- 
termittently  rotated  by  a  rachet  and  pawl.    The  work 
is  held  against  the  feeder  by  a  presser  foot  or  a 
wheel  attached  to  the  upper  end  of  the  frame. 

The  stitching  mechanism  varies  according  to  the 
kind  of  stitch  made,  which  may  be  one-  or  two-needle, 
one-  or  two-thread,  chain  stitch;  one-  or  two-needle 
lock  stitch;  buttonhole  stitch,  etc.  The  commonest 
are  the  one-needle,  one-thread  chain  stitch  (which  is 
strong  and  elastic,  but  has  a  right  and  a  wrong  side 
and  pulls  out  if  broken),  and  the  one-needle  lock 
stitch  (which  has  two  threads  and  does  not  stretch 


FIG.  184.     CHAIN  STITCH  MECHANISM 

easily,  but  cannot  pull  out).  Figure  184  shows  a 
common  chain  stitch  and  the  mechanism  that  forms 
it.  The  needle,  a,  descends  through  the  work,  carry- 
ing the  thread  with  it;  the  looper,  b,  rotating  clock- 
wise, catches  a  loop  of  the  thread  as  the  needle  rises; 
the  work  then  feeds,  the  loop  c  is  spread  laterally 
so  as  to  encircle  the  needle  on  its  next  descent;  and 
as  the  needle  takes  the  position  shown  in  the  figure, 
the  loop  c  is  cast  off  from  b  by  the  extension,  d,  and 
drawn  taut  as  the  needle  completes  its  downward 
stroke.  Another  method  of  forming  the  chain  stitch 
is  described  later,  in  connection  with  the  McKay  sew- 
ing machine. 

A  typical  lock-stitch  mechanism.  Figure  185,  has 
a  needle,  a,  the  bobbin  inclosed  in  case  b,  which  is 
supported  loosely  so  that  a  thread  can  completely 
encircle  it;  the  shuttle,  c,  and  shuttle  driver,  d,  oscil- 
lated by  shaft  e.  Both  c  and  d  move  in  a  circular 
path  in  the  frame,  f .    As  a  descends  it  pulls  down  a 


470 


THE  MECHANICAL  EQUIPMENT 


BOOT  AND  SHOE  MACHINERY 


471 


a-' 


n 


FIG.  185.      LOCK  STITCH.  MECHANISM 

loop  of  thread  which  is  caught  on  the  hook  of  the 
shuttle,  c,  as  it  rotates  clockwise  owing  to  the  pres- 
sure from  d,  and  is  drawn  into  the  position  shown. 
The  shuttle  rotates  slightly  farther,  while  the  needle 
rises  and  a  take-up    (not  shown)   pulls  the  needle 
thread  off  the  shuttle  hook  and  over  the  left  side  of 
the  bobbin,  so  as  to  loop  it  around  the  bobbin  thread; 
then    d    reverses    its    direction,    the    needle    thread 
passes  out  through  the  space  opened  up  by  the  back- 
lash between  c  and  d,  and  further  motion  of  the 
take-up  draws  the  stitch  taut  while  the  shuttle,  c, 


and  the  driver,  d,  return  to  their  first  positions, 
ready  for  the  next  descent  of  the  needle.  All  stitch- 
ing devices,  either  chain  stitch  or  lock  stitch,  re- 
quire a  tension  regulator  for  the  threads;  this  is 
usually  a  pair  of  discs  or  plates  held  together  by  a 
thumbscrew  and  spring,  between  which  the  thread  is 
drawn. 

The  eyeletting,  the  buttonholing,  and  the  making 
of  the  decorative  perforations  along  the  upper  edges 
of  tips,  are  also  done  in  the  stitching  room.  The 
eyeletting  machine  has  a  table  on  which  the  work  is 
placed,  a  punch  which  descends  upon  the  work  and 
perforates  it,  and  an  eyelet-placing  finger  which  re- 
ceives the  eyelets  from  a  magazine,  one  at  a  time 
and  flanged  on  one  end,  and  inserts  them  in  the  per- 
forations from  the  under  side.  A  set,  or  rivetter, 
descends  upon  each  eyelet  and  rivets  it  while  the 
finger  holds  it  in  place.  The  duplex  eyeletting  ma- 
chine sets  both  rows  of  eyelets  on  a  shoe  at  the  same 
time;  thus  perfect  alignment  is  insured. 

The  buttonholing  machine  is  a  special  sewing  ma- 
chine which  first  cuts  the  buttonhole  with  a  wedge- 
shaped  punch,  and  then  sews  it  with  a  two-thread 
stitch  that  covers  the  raw  edge  of  the  hole  and  in- 
closes a  cord  that  protects  it.  The  tip  perforations 
are  made  either  on  a  ** Crown"  machine,  a  bench 
machine  like  a  miniature  sheet-metal  punch,  which 
perforates  the  entire  tip  at  one  stroke;  or  on  a 
*' Royal"  machine,  which  has  a  C-frame  like  that 
of  a  sewing  machine,  the  needle  being  replaced 
by  a  punch  which  perforates  a  single  hole  or  unit  of 
the  design  and  simultaneously  feeds  the  work  into 


i 


472 


THE  MECHANICAL  EQUIPMENT 


position  for  making  the  next  perforation.  The 
wooden  cutting  block  of  the  dieing-out  machine  is  re- 
placed by  a  strip  of  paper  which  is  fed  along  under 
the  work. 

Machinery  of  the  Stock-Fitting  Room.— Stripping 
machines  are  used  for  cutting  hides  into  strips.  The 
individual  soles  or  heel  lifts  are  then  cut  from  the 
strips  on  dieing-out  machines. 

Rolling  machines,  which  compress  the  sole  leather 
to  make  it  more  durable,  consist  of  a  housing  for  an 
upper  and  a  lower  roll,  gearing  for  driving  them,  a 
screw  adjustment  for  varying  thicknesses  of  leather, 
and  a  treadle  for  raising  the  lower  roll. 

The  soles  are  only  roughly  cut  to  shape  on  the 
dieing-out  machines,  which  are  frequently  in  a  sepa- 
rate factory,  so  that  the  accurate  form  must  be  ob- 
tained on  a  rounding  machine.    The  *' Planet,"  illus- 
trated in  Figure  186,  has  a  circular  table,  a,  on  which 
is  mounted  a  fixture,  b,  for  holding  a  wooden  pattern, 
c,  shaped  to  the  desired  form  of  the  sole.    The  sole  is 
placed  between  this  pattern  and  a  plate,  d,  which  is 
pressed  down  from  above  and  is  adjustable  for  differ- 
ent thicknesses  of  stock.    A  short  vertical  knife,  e,  is 
held  in  a  block  at  the  end  of  a  swinging  arm,  g,  which 
is  pressed  against  the  pattern  by  a  spring.    When  the 
power  is   applied,   the   table   and    the   knife   rotate 
rapidly  in  a  counter-clockwise  direction  for  a  little 
more  than  one  revolution,  to  insure  a  complete  trim- 
ming of  the  surplus  material,  and  then  return  to  their 
original  position.  During  this  interval  the  knife  block 
has  been  in  continuous  contact  with  the  pattern,  and 
has  made  an  exact  reproduction  in  the  leather  stock. 


472 


TUK  ME(  HANK  AL  EQlIPMExNT 


position  for  nuikino-  tlio  noxt  perforation.  Tli< 
wooden  vniViuii;  ])iock  of  the  dieino:-out  nuichine  is  re- 
placed ])y  a  strip  of  pai)er  which  is  fed  along  undci 
tlie  work. 

Machinery  of  the  Stock-Fitting  Room.— Stripping 
machines  are  used  for  cutting  hides  into  strips.  The 
individual  soles  or  heel  lifts  are  then  cut  from  the 
strips  on  dieing-out  nuichines. 

Kolling  nuichines,  wliich  compress  the  sole  leatlior 
to  nudve  it  more  durable,  consist  of  a  housing  for  an 
upper  and  a  lower  roll,  gearing  for  driving  them,  a 
scn^w  adjustnu^nt  for  varying  thicknesses  of  leather, 
and  a  treadle  for  raising  the  lower  roll. 

The   soles   are   only    roughly   cut   to   shape   on   the 
dieing-out  nuu'hines,  wliich  are  frecjuently  in  a  sepa- 
rate factory,  so  that  the  accurate  form  must   be  ob- 
tained on  a  rounding  nuichine.     The  **Planet,''  illus- 
trated in  Figure  ISfi,  has  a  circular  table,  a,  on  which 
is  mounted  a  fixture,  b,  for  holding  a  wooden  pattern, 
c,  shaped  to  the  desired  form  of  th(^  sole.     The  sole  is 
placed  between  this  pattern  and  a  plate,  d,  which  is 
pressed  down  from  al)ove  and  is  adjustable  for  differ- 
ent thicknesses  of  stock.     A  short  vertical  knife,  c,  is 
held  in  a  block  at  the  end  of  a  swinging  arm,  g,  wiiich 
is  pn^ssed  against  tlip  pattern  l)y  a  spring.    When  the 
power    is    applied,    the    table    and    the    knife    rotate 
rapidly   in  a   count(M*-clockwise  direction   for  a  little 
more  than  oue  revolution,  to  insure  a  complete  trim- 
ming of  the  surplus  uuiterial,  and  then  return  to  their 
original  position.    During  this  interval  the  knif(^  block 
has  be,»Ti  in  continuous  contact   with  the  pattern,  an<I 
has  made  an  exact  repi'oduction  in  the  leather  stock. 


474  THE  MECHANICAL  EQUIPMENT 

It  always  presents  the  knife  edge  squarely  to  the 
work;  and  a  cam,  f,  shaped  roughly  to  the  outline  of 
tne  sole,  helps  the  spring  to  keep  a  uniform  pressure 
ot  the  swinging  arm,  g,  against  the  pattern,  and 
prevents  the  knife  from  leaving  it  when  rounding 
sharp  corners. 

The  channeling  of  the  soles   (see  Figure  181)   is 
done  on  machines  similar  to  those  used  for  heavy 
skivmg;  the  work  is  fed  between  rolls  against  a  sta- 
tionary knife,  which  is  adjusted  to  cut  a  slit  in  the 
leather  instead  of  shaving  off  its  surface.  For  Good- 
year welt  insoles  two  channels  are  cut  simultaneously, 
one  m  the  outer  edge  extending  toward  the  center, 
and  the  other  in  the  lower  surface. 
^   The  manufacture  of  heels  has  developed  into  an 
independent  industry.     After  the  lifts,  or  separate 
layers  have  been  cut  out  the  heels  are  assembled  in 
a  heel-building  machine,  consisting  of  a  horizontal 
bed  on  which  are  set  three  adjustable  guides  or  jaws, 
a  clamp  for  holding  the  lifts  together,  and  a  nailing 
device   for   driving   the    required    number    of   nails 
through  them     There  is  also  a  cement  reservoir  and 
a  row  of  small  bins  on  each  side  of  the  bed,  for  hold- 
ing sizes  of  lifts.    The  operator  first  places  nails  in  a 
plunger  plate  under  the  bed;  he   then   selects   the 
proper  lifts  from  the  bins,  dips  them  into  the  cement 
^ervoir,  and  ays  them  on  the  bed  between  the  jaws. 
When  a  treadle  is  pressed  the  jaws  are  moved  to- 
gether  and  the  lifts  are  lined  up;  the  power  is  applied, 
clmnpmg  the  lifts  together  and  driving  the  nails 

Bottoming-Room  Machinery.-The  machines  of  this 
department  fall  into  three  classes:   lasting  machines 


BOOT  AND  SHOE  MACHINERY 


475 


stitching  machines,  and  moulding  and  leveling  ma- 
chines.  Lasting  consists  of  three  operations:  assem- 
bling the  upper  and  the  insole  upon  the  last;  *' pulling 
over,"  or  drawing  the  toe  part  of  the  upper  down 
over  the  front  end  of  the  insole;  and  lasting  proper, 
which  is  a  continuation  of  the  pulling-over  process  all 
around  the  sole.  Tacking  machines  first  nail  the  in- 
sole to  the  last  and  fasten  the  upper  to  the  last  at 
the  heel  by  two  tacks  driven  part  way  in.  The  next 
operation  takes  place  on  the  pulling-over  machine 

(Figure  187). 

The  principal  parts  of  this  machine  are  as  follows: 
adjustable  rests  for  the  last  and  the  heel;  pincers, 
one  at  the  toe  and  the  others  on  each  side  near  the 
toe;  levers  for  shifting  the  positions  of  the  pincers 
by  hand  after  they  have  gripped  the  upper,  in  order 
that  the  toe  may  be  exactly  centered;  devices  for 
drawing  the  upper  over  the  edge  of  the  last,  and  for 
moving  the  pincers  toward  each  other,  thus  laying 
the  upper  against  the  bottom  of  the  last;  and  auto- 
matic magazine-fed  hammers  for  driving  temporary 
nails  through  the  upper  and  the  insole.  The  great 
advantage  of  the  work  of  this  machine  as  compared 
with  hand  lasting,  aside  from  the  saving  of  time,  is 
that  the  tension  is  applied  evenly  all  around  the  toe 
rather  than  at  one  point  at  a  time,  and  the  workman 
can  see  without  effort  whether  the  upper  is  straight 
and  tight  before  he  drives  the  tacks. 

The  final  lasting  is  done  on  a  **bed  type"  machine, 
the  essential  feature  of  which  is  a  pair  of  wipers  at 
the  toe  and  heel.  The  shoe  is  held  bottom  side  up 
in  an  adjustable  rest;  two  pairs  of  plates  are  then 


476 


THE  MECHANICAL  EQUIPMENT 


BOOT  AND  SHOE  MACHINERY 


477 


moved  forward,  drawing  or  ** wiping''  the  upper 
closely  around  the  edge  of  the  sole  at  the  heel  and 
toe.  The  operator  then  nails  down  the  upper  all 
around  the  sole  except  at  the  heel,  with  a  rapid-fire 
tacker,  holding  the  upper  with  pincers  in  his  left 
hand  while  he  hammers  with  his  right.  The  nails 
are  temporary  for  Goodyear  welt  and  turn  soles,  but 
are  driven  clear  in  and  clinched  against  an  iron 
plate  on  the  sole  of  the  last  in  making  McKay,  stan- 
dard-screw, and  pegged  shoes.  The  wipers  are  then 
shd  back,  and  the  lasting  is  complete. 

The  stitching  is   done   on   a  McKay,   a   Goodyear 
welt,  or  a  Goodyear  outsole  machine,  according  to  the 
location  of  seam  and  kind  of  shoe.    Figure  188  shows 
a  McKay  machine  which  consists  of  a  head,  a,  con- 
taining the  feeding  and  stitching  mechanism,  and  a 
turntable,   b,   which   supports   the   horn,   c,   and   the 
thread-waxing  device,  both  of  which  are  heated  by 
steam  or  gas.    In  operation  a  shoe,  after  the  last  has 
been  removed,  is  placed  upside  down  on  the  horn, 
where  it  is  held  by  a  presser  foot,  and  the  stitching 
mechanism,    shown    in    Figure    189,    forms    a    chain 
stitch.     The  thread  comes  up  through  the  horn,  a, 
Figure  189,  and  is  laid  in  the  barb,  c,  of  the  needle 
by  the  whorl,  b;  then  the  needle  rises  with  a  loop  of 
thread  while  the  moving  guard,  d,  is  in  the  dotted 
position,  but   when  it  starts   to   descend   the   guard 
moves  to  the  left  and  holds  the  loop  in  place,  so  as 
to  enchain  the  loop  that  is  drawn  through  from  be- 
low on  the  next  rise  of  the  needle. 
I     The  Goodyear  welt  machine  makes  a  chain  stitch 
■  by  the  same  general  method,  modified  in  details  so 


FIG.  189.    M  'kay  chain  stitch  mechanism 

that  a  surface  stitch  (see  Goodyear  welt  inseam,  Fig- 
ure 181,  b),  instead  of  a  through  stitch — is  made. 
Thus  the  needle  is  curved  instead  of  straight,  and, 
instead  of  supporting  the  shoe  on  a  horn,  the  opera- 
tor holds  it  between  a  back  rest  and  a  guide  which 
enters  the  surface  channel  and  bears  the  thrust  of  the 
needle.  There  is  also  a  guide  for  feeding  the  welt 
into  position,  which  can  be  removed  when  turn  §oles 
are  being  stitched. 

The  Goodyear  outsole  machine  makes  a  lock  stitch 
by  a  method  differing  materially  from  that  of  the 
plain  sewing  machine.    Instead  of  the  needle  thread's 


I 


478  THE  MECHANICAL  EQUIPMENT 

being  fed  from  above  and  the  shuttle  thread  from 
Delow,  their  positions  are  reversed.  The  needle  itself 
remains  on  the  upper  side,  being  barbed  so  as  to  pull 
the  needle  thread  through  from  the  under  side.  A 
reciprocating  awl  makes  the  holes,  and  a  take-up 

Zl  Tl  "?•  *^'  '^^'^  ^  *^«  th^««ds  after  each 
stitch,  duplicating  m  a  clever  and  very  rapid  way 

the  work  of  the  old  time  shoemaker.  Other  essential 
parts  of  the  machine,  also  found  on  the  McKay  and 
Goodyear  welt  machines,  are:  (1)  steam  heating  sys- 
tem for  the  waxed  thread,  (2)  thread-waxer,  (3) 
thread-tension  regulator. 

Moulding  and  leveling  machines  are  of  two  kinds: 
those  which  roll  the  sole,  and  those  which  shape  it 
by  direct  pressure  between  dies.    They  are  built  with 
two  umts  in  tandem,  so  that  the  operator  can  set  up 
one  shoe  while  another.is  under  pressure.    The  Good- 
year sole-leveling  machine,  of  the  first  type,  holds  the 
shoe  upside  down  on  a  jack,  while  a  concave  brass 
roller  is  passed  back  and  forth  and  from  side  to  side 
over  the  sole,  the  pressure  being  applied  by  a  treadle. 
Ihe   Goodyear  sole-laying   machine   belongs   to   the 
direct  pressure  type;  it  consists  of  a  lower  head  sur- 
mounted by  a  rubber  die  block,  and  an  upper  head  to 
which  the  shoe  is  attached,  the  two  heads   being 
drawn  together  by  power.    The  Hercules  type  com- 
bines direct  pressure  and  rolling,  by  having  the  shoe- 
holding  jack  and  the  die  that  shapes  the  sole  swing 
cu  pivoted  arms,  instead  of  sliding  in  guides 

Rmshing-Room  Machinery.-Most  of  this  is  typical 
bufling  and  polishing  equipment:  high-speed  spindles 
on  which  are  mounted  milling  cutters,  emery  wheels 


I 


II' 


FIG.  190.     NAUMKEAG  BUFFING  MACHINE 

United  Shoe  Machinery  Co. 

479 


478 


THE  MECflAMCAL  EQUIPMENT 


being  fed  from  above  and  the  shuttle  thread  fron. 
Delow,  their  positions  are  reversed.    The  needle  itself 
remains  on  the  npper  side,  being  l.arl.ed  so  as  to  pull 
the  needle  thread  through  from  the  under  side.      \ 
reciprocating   awl   makes   the   holes,   and   a   take-up 
lev-er  draws  up  the  slack  in  the  threads  after  each 
stitch,  duplicating  in  a  clever  and  verv  rapid   wav 
the  woi-k  ot  the  old  time  shoemaker.    Other  essential 
parts  of  the  machine,  also  found  on  the  McKay  and 
Goodyear  welt  machines,  are:  (I)  steam  heating  sys- 
tem   tor   the    waxed    thread,    (2)    thread-waxer,    (3) 
thread-tension  regulator. 

Moul.ling  and  leveling  machines  are  of  two  kinds- 
those  which  roll  the  sole,  and  those  which  shape  i1 
by  direct  pressure  between  dies.    Thev  are  built  with 
two  units  m  tandem,  so  that  the  operator  can  set  up 
one  shoe  while  another  is  under  pressure.    The  Good- 
year sole-leveling  machine,  of  the  tirst  tvpe,  holds  the 
shoe  upside  down  on  a  jack,  while  a  Concave  brass 
roller  is  passed  back  and  forth  and  from  side  to  side 
ov'er  the  sole,  the  pressure  being  applied  by  a  treadle, 
llie    Goodyear   sole-laying    machine    belongs    to    the 
direct  pressure  type;  it  consists  of  a  lower  head  sur- 
mounted by  a  rubber  die  block,  and  an  upper  hea.l  to 
which    the   shoe   is   attached,    the    two   heads    bein- 
drawn  together  by  power.     The  Hercules  tvpe  com- 
bines direct  pressure  and  rolling,  by  having  the  shoe- 
liolding  jack  ami  the  die  that  shapes  the  sole  swin- 
en  pivoted  arms,  instead  of  sliding  in  guides 

Finishing-Room  Machinery.-ilost  of  this  is  typical 
bufling  and  polishing  equipment:  high-speed  spindles 
on  which  are  mounted  milling  cutters,  emerv  wheels 


FIG.   190.      NAUMKEAG   BUFFING   MACHINE 

United  SIkip  Mucliincry  (^'o. 

4711 


7 


480 


THE  MECHANICAL  EQUIPMENT 


sandpaper  wheels,  brushes  and  buffing  wheels.  The 
ironing  machine  is  fitted  with  small  blocks  or  disks 
of  iron,  heated  by  a  gas  flame,  and  vibrated  or  rotated 
rapidly  so  as  to  burnish  the  surface  of  the  leather. 
The  Naumkeag  buffing  machine,  Figure  190,  is  in  a 
class  by  itself.  This  machine  has  two  vertical  spin- 
dles, a  and  b,  for  rough  and  fine  polishing  respec- 
tively, at  whose  lower  ends  are  the  emery-covered 
rubber  pads,  c,  d.  These  pads  are  distended  by  com- 
pressed air;  thus  a  delicate,  yielding  pressure  is 
obtained,  and  a  smooth,  velvet  surface  is  given  to 
the  work. 


CHAPTER  XXVI 
TEXTILE  MACHINERY 

The  Fibres  and  the  Processes.— Since  the  manufac- 
ture of  woven  fabrics  is  one  of  the  oldest  industries, 
it  is  natural  that  man's  ingenuity  should  have  devised 
and  perfected  an  almost  endless  variety  of  machinery 
for  making  this  product.  Within  the  confines  of  a 
single  chapter,  however,  it  is  possible  to  describe  only 
typical  machines,  and  merely  to  give  the  reader  a 
broad  survey  of  the  subject  which  may  serve  as  an 
introduction  to  a  more  detailed  study.  The  four  prin- 
cipal fibres  used,  in  the  order  of  their  importance, 
are  cotton,  wool,  silk,  and  linen.  The  processes  in- 
volved are  spinning,  which  includes  cleaning  and 
straightening  the  fibres,  drawing  them  out  and  twist- 
ing them  into  yarn;  weaving  and  knitting;  and  finish- 
ing, which  comprises  a  number  of  processes  for  im- 
proving the  appearance  of  the  rough  web  of  cloth. 
In  the  manufacture  of  reeled  silk,  a  process  known 
as  throwing  replaces  the  operations  of  spinning. 

Cotton-Spinning  Machinery. — The  opening  and 
cleaning  of  the  fibres  is  done  in  openers  and  pickers. 
The  essential  part  of  both  machines  is  a  beater,  or 
set  of  rapidly  revolving,  blunt  steel  blades,  which 
clean  the  cotton  over  a  grid.  In  the  opener,  the  cot- 
ton taken  from  the  bale  is  dumped  into  a  hopper, 

481 


482 


If 


THE  MECHANICAL  EQUIPMENT 


PIG.  191.      BREAKER  PICKER 


.rom  which  It  IS  carried  on  conveying  aprons  to  a 
doffer,  or  four-bladed  drum,  for  a  preliminary 
cleamng  before  it  goes  to  the  beater.  From  this  point 
it  IS  blown  through  an  air  duct,  or  ** trunk,''  to  the 
pickers,  which  are  generally  arranged  in  series  of 
three— breaker,  intermediate,  and  finisher. 

Figure  191  illustrates  the  working  parts  of  a 
breaker  picker;  a,  is  a  screen  drum  connected  at  both 
ends  with  the  intake  of  fan,  b,  and  revolving  around 
the  semi-cylindrical  shield,  c.  The  cotton  enters 
through  trunk,  d,  adheres  to  the  drum  while  dust 
passes  through,  is  stripped  off  by  roll,  e,  at  a  point 
where  the  shield,  c,  prevents  further  adhesion,  and 
drops  into  the  gauge  box,  f.    This  box  acts  as  a  reser- 


TEXTILE  MACHINERY 


483 


voir  to  compensate  for  irregularities  in  the  supply 
and  discharge  of  cotton;  any  surplus  overflows  into 
the  space,  g,  from  which  it  can  be  removed  through  a 
door.  The  material  in  the  gauge  box  is  carried  for- 
ward on  the  apron,  h,  and  between  the  feed  rolls,  i, 
to  the  beater,  j,  which  pulls  it  off  in  tufts  and  throws 
it  against  the  grid,  k,  through  which  dirt  falls,  while 
the  cotton  is  blown  over  the  dust-catching  grate,  1,  to 
the  screen  drums,  m,  m,  which  act  very  much  like  the 
screen,  a.  It  is  then  stripped  off  in  an  even  sheet,  or 
**lap,"  by  rolls,  n,  passed  between  weighted  calenders, 
0,  and  reeled  on  the  roll,  p.  The  intermediate  and 
finisher  pickers  have  not  the  gauge  box  or  the  screen, 
a,  but  have  racks  for  holding  four  laps,  which  are 
unwound  on  the  apron  corresponding  to  h. 

The  lap  (f,  Figure  192),  coming  from  the  finisher 
picker  is  practically  free  from  dirt,  and  the  fibres  are 
ready  to  be  straightened  out.  This  is  done  by  means 
of  a  card.  Figure  192,  which  combs  them  between  two 
surfaces  covered  with  fine  pins.    The  picker  lap,  f,  is 


/Vv//////////wW>y////vw^^^ 


PIG.  192.      COTTON  CARDING  MACHINE 


ii 


484 


THE  MECHANICAL  EQUIPMENT 


TEXTILE  MACHINERY 


485 


unrol  ed  by  rolls,  g  and  h,  and  presented  to  the 
rapidly  revolving  leader,  a,  which  carries  it  over  the 
knife,  I,  and  grate,  j,  where  any  remaining  dirt  is 
rennoved,  to  the  cylinder,  b.    Since  the  surface  speed 
ot  the  cylinder  is  more  than  twice  that  of  the  leader, 
the  cotton  IS  picked  up  by  the  forward-pointing  card 
teeth,  b',  and  carried  under  the  slowly  moving  flats  c 
which  ar6  also  faced  with  carding  teeth.    Here  the 
pulling  action  on  the  fibres  commences,  and  continues 
until  the  head  end  of  the  chain  of  flats,  c',  is  reached, 
ihe  cotton  may  travel  around  the  cylinder  a  num- 
ber of  times,  but  it  is  eventually  pulled  off  by  the 
pins  of  the  slowly  revolving  doffer,  d;  and  since  it 
rests  lightly  on  the  surface  it  is  easily  removed  by 
the  vibrating  comb,  e,  and  is  fed  in  a  lap  to  the 
calender,  k,  which  thins  it  and  narrows  it  down  to 
what  IS  termed  a  "sliver."    It  then  passes  through 
an  automatic  coiler  into  the  can,  1.    One  might  think 
that  If  the  doffer  removes  fibres  from  the  card  cylin- 
der, the  flats  would  do  the  same  thing;  this,  however, 
IS  prevented  by  the  stripping  knife,  m.    In  order  to 
keep  a  card  in  working  condition,  it  is  necessary  to 
grind  the  cylinder,  doffer,  and  flats  frequently,  and 
to  strip  the  doffer  and  the  cylinder  three  or  four 
times  a  day.    For  this  purpose  special  bearings  are 
provided  on  the  frame,  in  which  grinding  wheels  and 
stripping   brushes   may   be   placed    when   they   are 
needed. 

The  Comb.— In  the  manufacture  of  long  staple  yarn, 
the  cotton  is  passed  through  an  additional  machine, 
called  a  comb,  the  purpose  of  which  is  to  remove  all 
short  fibres.    The  card  slivers  are  first  "drawn  "  or 


I 


stretched  out,  and  combined  into  a  lap  about  12 
inches  wide,  which  is  wound  on  a  roll.  The  laps  are 
fed  to  the  comb  cylinders,  which  are  covered  half-way 
around  with  fine  needles.  These  pick  off  tufts,  re- 
move the  short  fibres,  and  pass  the  long  ones  out 
between  detaching  rolls  and  through  a  trumpet,  which 
contracts  them  to  a  new  sliver.  The  long  fibre  slivers 
are  then  fed  through  a  calender,  combined  by  draw- 
ing rolls,  and  coiled  in  a  can.  The  short  fibres  are 
removed  from  the  cylinder  needles  by  a  revolving 
brush,  and  collected  in  a  thin  lap  by  a  doffer  comb 
similar  to  that  on  a  carding  machine. 

Drawing  Frame;  Ply  Frame;  Spinning  Machine.— 
The  last  steps  in  spinning  are  carried  out  on  three 
kinds  of  machines:  the  drawing  frame,  which  com- 
bines the  slivers  from  six  or  eight  cans  and  draws 
them  out  by  means  of  rollers;  the  fly  frame,  which 
continues  the  drawing  process  and  gives  the  sliver  a 
slight  twist,  converting  it  into  a  loose  yarn,  called 
** roving";  and  the  spinning  machine,  which  twists 
the  roving  sufficiently  to  make  it  into  a  fairly  hard 
yarn,  at  the  same  time  drawing  it  slightly.  Fly 
frames  are  generally  arranged  three  in  a  series:  the 
first,  or  ** slubber,"  the  intermediate,  and  the  fine. 
Figure  193  shows  a  section  of  a  fine  fly  frame.  The 
course  of  the  roving  is  from  the  bobbins,  a,  held  ij;i 
a  rack  called  a  ** creel,"  thence  through  the  drawing 
rolls,  b,  where  the  ends  from  each  pair  of  bobbins 
are  united,  thence  to  the  flyers,  c,  and  down  one  arm 
of  each  flyer  and  on  to  the  bobbins,  d. 

The  flyers  are  mounted  on  spindles,  e,  which  are 
driven  at  constant  speed,  while  the  bobbins  are  on 


I 


186 


THE  MECHANICAL  EQUIPMENT 


TEXTILE  MACHINERY 


487 


1FT 


PIG.  193.     PLY  PRAME 

eoncentric  but  independently  driven  spindles,  f  The 
rotation  of  the  flyers  imparts  a  twist  to  the  roving 
and  the  excess  of  speed  of  the  bobbins,  d,  over  that 
of  the  flyers  serves  to  wind  this  roving  on  the  bob- 
bins In  order  that  they  may  wind  the  bobbins 
evenly,  the  spindles,  f,  are  carried  on  a  rail,  which  is 
moved  np  and  down  by  a  builder  mechanism,  and  the 


spindle  speed  is  decreased  by  an  automatic  tension 
gear  as  the  bobbins  fill  up.  A  standard  fly  frame 
contains  a  row  of  thirty  or  more  pairs  of  these  flyers, 
set  side  by  side  as  close  as  possible. 

The  spinning  machine  is  one  of  three  types:  ring 
frame,  cap  frame,  or  mule.  The  first  two  are  most 
widely  used,  owing  to  their  greater  simplicity  and 
cheapness  of  operation.  Like  the  fly  frame,  they 
twist  and  wind  simultaneously,  whereas  the  mule 
performs  these  operations  successively  on  a  definite 
length  of  yarn,  and  then  passes  on  to  the  next  length. 
In  the  ring  frame  the  bobbin  is  positively  driven, 
while  a  wire  loop  sliding  on  a  stationary  ring  encir- 
cling the  bobbin  is  moved  solely  by  the  pull  of  the 
yarn  passing  to  the  bobbin.  At  the  same  time,  the 
friction  between  ring  and  loop  is  sufficient  to  hold  the 
loop  back  and  give  the  difference  in  speeds  necessary 
for  winding.  All  the  rings  of  one  frame  are  mounted 
on  a  rail,  which  rises  and  falls  automatically  so  as  to 
wind  the  bobbins  evenly.  In  the  cap  frame,  the  bob- 
bin and  its  spindle  are  the  only  moving  parts  of  the 
spinning  mechanism;  a  close-fitting  stationary  cap 
fits  down  over  the  bobbin,  and  the  yarn,  in  order  to 
reach  it,  has  to  pass  under  the  lower  edge  of  this 
cap.  The  resulting  friction  retards  the  yarn  suffi- 
ciently to  cause  winding. 

The  mule  is  an  extremely  complicated  machine  and 
requires  skill  to  operate  and  keep  in  repair.  Its 
essential  parts  are  the  creel,  a.  Figure  194,  holding 
the  roving;  a  carriage,  b,  supporting  a  row  of 
spindles,  c;  and  a  head  (not  shown)  containing  the 
driving   mechanism.      The   roving    passes    from    the 


n 


v\ 


488 


THE  MECHANICAL  EQUIPMENT 


*^  ^^^^^^^im„„5„^ 


^mmm//m 


FIG.  194.     SPINNING  MULE 

faller    h      Tho  f^ii      •    ''^"^"^  ^^^^^r,  g,  and  counter- 
of  opin^  '""^"^"^  ^^«  *^«  «t«P«  -  one  cycle 

from'?L*drarZ'  71"  .''°"*  '"^  ^^^^^^  ^-^^ 
om  ine  dratt  rolls,  while  the  roving  is  naid  n„f 

lakeTfew  ria^j'  TT  ^*°^^'  ^'^^  ^^^^'^ 
,il«ri„  ^        J  backward  turns  to  unwind  the  irres 

fnZl2  -^  *^'  ^^™  ^'^^^  accumulated  on  tol, 
during  this  spinning,  and  the  fallers  take  the  J,7 
tions  shown  bv  the  dnttaA  r         x,  P^^^' 

actinff  as  a  JI I      •  ''"^''  *^  counterfaller 

DODDin.     Third,  the  carriage  runs  back  to  its  oris 
anal  position,   and   the   spindles   rotate   slowly  Z 


TEXTILE  MACHINERY 


489 


wind  up  the  yarn  that  has  just  been  spun,  the  fallers 
moving  up  and  down  in  such  a  way  as  to  wind  the 
yarn  evenly  and  under  uniform  tension.  Fourth,  the 
carriage  stops,  and  the  fallers  return  to  their  position. 

Wool-Spinning  Machinery.— All  raw  wool  contains 
a  quantity  of  grease  and  dirt,  which  must  be  re- 
moved in  dusters  and  scourers.  The  dusters  are 
horizontal  skeleton  con^s  with  inwardly  projecting 
pins,  rotating  in  an  air-tight  chest,  which  acts  like  a 
tumbling  barrel;  the  wool  enters  at  the  small  end  of 
the  cone  and  leaves  at  the  large  end,  while  dust  is 
drawn  out  through  a  fine  screen  above  the  cone  and 
larger  particles  of  dirt  drop  through  a  coarse  screen 
below  it.  The  scourers  are  shallow  troughs,  or, 
** bowls,"  about  3  feet  wide  and  16  to  40  feet  long, 
fiilled  with  a  warm  solution  of  soft  soap,  into  which 
the  wool  is  fed  and  paddled  along  by  a  series  of 
.  rakes,  which  enter  the  liquor  vertically,  advance 
about  twelve  inches,  rise  from  the  bowl,  and  return 
to  their  first  position.  This  motion  is  necessitated 
by  the  nature  of  the  wool  fibres,  which  are  very 
easily  felted  or  matted  under  the  action  of  heat  and 
agitation,  on  account  of  the  scales  that  cover  their 
surface.  On  reaching  the  end  of  the  bowl,  the  wool 
passes  between  squeezing  rolls  to  the  next  scouring 
bowl  or  to  a  rinsing  bowl  filled  with  running  water 
instead  of  washing  liquor.  After  washing,  the  wool 
is  carried  on  a  perforated  apron  through  the  drier, 
a  closed  chamber  about  20  feet  long,  where  it  is  dried 
by  a  forced  circulation  of  warm  air. 

The  rest  of  the  preparation  of  the  fibres  for  the 
spinning  frames  depends  upon  whether  they  are  to 


I 


^^^^H 

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^^^^H, 

^^m 

^^^^m 

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1  ! 

^^^^H 
^^^^^■p 

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^^^^^■^ 

iHH 

■ 

11 

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11 

^VH| 

H 

^^^^^^^H 

^■^^^H 

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UM 

^^^H     1 

490 


THE  MECHANICAL  EQUIPMENT 


cQTv,^  4?       ..•  "i^dKer,  and  taisher,  performs  thp 

flaS  ther^        ."^  '''  ''"""  ^^'•^«'  ^-^^  -«t^a<i  « 
'Wkers»  "^^"^  ^'"^"^  t^^t'^^d  rolls  called 

inder  wLh    .      ?.  ''"'"  *°  ^'^^  ^^^^^^^  °f  the  cyl- 
inder, which  straighten  out  and  even  the  fibres     jL 

ratesMe'fir"'  ^\^  '^^^^'  «  toothed  "fancy  roll'' 
the  case  of  K'''r  ^'^^^  '^'^  ^^«  ^^^^'^  ^^d-    In 
he  doffer  .^'k  !,'  '^'^''  ^^'^  ^''  then  collected  by 
o  layth /r  '  ^'■^"".^"to  a  sliver  from  the  side! 
Sie  finisher  .r^  "-regularly,  and  wound  into  balls 
ste«d  of ?  "^  ^^'  ^^'^  ^"ff^'-^'  e««h  of  which  in- 

nating  rings  of  teeth  and  leather  about  an  inch  wide 

r^  ''  anTr  T""  'T  '""^'^  ™^^  ^^^  ^  '  "^Pe 
sTstin/nf  /        *^™"^^   ""  ^Pr°"   condenser,   con- 
on  aft  witT  T"l  '"'^  ^  '''"^^  ^Pr^'^  traveling  in  • 
contact  with  the  slivers  and  oscillating  at  the  time 

aTh    Hv"rttV°-f  ^'  *'^  ^^^^*  ''  -'"^^  -  to  rub 
eacn  sliver  into  a  loose  round  roving     The  rnvir,<r« 

for  w     .  f  ^'""""^   Machinerjr._Carding    machines 
yarn,  but  the  teeth  are  so  spaced  and  the  rolls  «,o 

known  !s  <S.         "^    f  ^  '*^P'^  ^°°^«'  the  process 

qir  a  serirof'""^      ''''^^'''  ^^^^'"S"     ™«  >•«- 
quires  a  series  of  nine  or  ten  gill  boxes,  which  are 

Xf  rth:?r?'*^""^  ^"^  '^^^"^  t''^  fibres  par! 
aliel,  by  the  following  simple  method:  The  loose  wool 

straightened  as  much  as  possible  by  hand, tfed Te-' 


TEXTILE  MACHINERY 


491 


IF///"/////////////////////////^^ 
SECTION    2-Z 


^:^ 


I' 


! 


Ill 


«  ! 


no.  195.     NOBLE  COMB 


492 


THE  MECHANICAL  EQUIPMENT 


tween  two  fluted  rolls  and  caught  on  pins  projecting 
from  a  series  of  bars  called  fallers,  which  travel  con- 
siderably faster  than  the  rolls.  These  pull  out  the 
fibres.  On  reaching  the  end  of  the  faller  travel,  the 
lap  passes  between  a  second  pair  of  rolls,  revolving 
at  still  higher  speed,  which  pull  it  out  still  further. 
In  each  passage  of  the  wool  through  a  gill  box,  the 
lap  is  pulled  out  from  ten  to  forty  times  its  original 
length. 

At  this  stage  the  short  fibres  (or  **noil")  which 
are  unsuited  for  worsted  yarn,  are  separated  from 
the  long  ones  in  a  comb,  one  form  of  which  is  shown 
in  Figure  195.  A  ring,  about  five  feet  in  diameter, 
carries  several  rows  of  pins,  a,  a  circular  creel  hold- 
ing balls  of  wool,  b,  and  a  set  of  conductors,  c, 
through  which  the  slivers,  d,  pass  on  their  way  from 
the  creel  to  the  pins.  Inside  this  ring,  and  revolving 
in  the  same  direction  and  with  approximately  the 
same  peripheral  speed,  are  the  rings,  e,  e,  also  pro- 
vided with  pins.  As  seen  in  the  sectional  views,  the 
conductors  are  hinged  at  their  outer  ends,  and  the 
inner  ends  are  narrowed  to  keep  the  slivers  from 
slipping  back.  At  x-x,  the  ends  of  the  slivers  rest 
in  the  pins,  as  shown;  at  y-y,  an  additional  length 
is  fed  out  by  tilting  the  conductors  while  keeping 
the  sliver  ends  in  the  pins  by  means  of  the  bar,  f; 
at  z-z,  knives,  g,  lift  the  slivers  off  the  pins;  and  at 
the  point  of  tangency  of  the  rings,  dabbing  brushes 
push  the  slivers  down  into  the  pins  of  both  the  large 
ring  and  the  pair  of  small  ones,  e,  e. 

The  further  rotation  of  the  rings  causes  the  sets 
of  pins  to  separate  from  each  other,  and  the  short 


TEXTILE  MACHINERY 


493 


fibres  are  pulled  out  and  stick  to  the  pins  on  the 
rings,  e,  e,  while  the  long  fibres  remain  on  the  large 
ring,  projecting  inwardly  in  a  long  fringe,  which  is 
pulled  off  by  the  fluted  rolls,  h,  and  delivered  in 
sliver  form  to  a  can.  Some  of  the  long  fibres  adhere 
to  the  rings,  e,e;  these  are  removed  by  the  rolls,  i, 
while  the  noil  is  stripped  by  knives  (not  shown)  set 
between  the  rows  of  pins.  This  machine  makes  an 
extremely  well-blended  product,  as  it  combines  sev- 
enty-two slivers  into  one. 

The  remaining  treatment  in  the  preparation  of  the 
yarn  consists  of  additional  drawing,  followed  by 
twisting,  for  which  gill  boxes  and  fly,  ring  and  cap 
frames  are  employed.     Soft  yarns  are  spun  on  the 

mule.  .  .     J     i. 

Linen  and  Silk  Preparation.— Flax  is  received  at 

the  spinning  mills  in  bunches  of  long  filaments  of 
**line,"  from  which  the  short  pieces  or  **tow"  must 
be  removed  by  *' hackling."  This  is  still  done  largely 
by  hand,  in  spite  of  the  existence  of  machines 
for  the  purpose.  The  process  consists  of  grasping 
one  end  of  a  bunch  of  flax  in  the  hand  or  holder, 
and  pulling  it  through  combs  set  with  progressively 
finer  and  finer  teeth.  The  bunches  then  pass  through 
a  *'spreadboard,"  where  they  are  combed  and  made 
into  a  continuous  sliver,  a  number  of  which  are 
combined  and  drawn  repeatedly,  after  which  they  are 
spun  on  ring,  cap,  or  fly  frames. 

Keeled  silk,  consisting  of  strands  of  six  to  twelve 
or  more  elementary  filaments,  is  wound  onto  bobbins 
and  ** thrown,"  i.  e.,  twisted  and  doubled  with  other 
strands.     The  twisting  is   generally  done   on  a  fly 


494 


THE  MECHANICAL  EQUIPMENT 


frame,  and  the  doubling  is  done  on  a  machine  that 
winds  the  threads  from  a  number  of  bobbins  onto  a 
smgle  bobbin.  After  each  doubling,  a  twist  is  given 
to  the  thread  in  the  direction  opposite  to  that  in 
which  the  original  strands  were  twisted.  Spun  silk 
manufactured  from  silk  waste,  is  beaten,  combed  or 
hackled,  drawn,  and  spun  on  machines  that  are  in  the 
mam  similar  to  those  which  perform  these  operations 
on  other  textile  materials. 

Weaving  Machinery.-Filling  thread  is  ready  for 

the  loom  shuttle  as  soon  as  it  has  been  wound  on 

cops  or  bobbins,  but  warp  threads  require  additional 

preparation    in    spoolers,    warping    machines,    and 

slashers.    The  purpose  of  the  spooler  is  to  wind  the 

warp  thread  from  the  spinning-frame  bobbins  onto 

large  spools,  each  of  which  holds  sufficient  thread  to 

extend  the  length  of  a  warp  without  piecing.     The 

spools  are  mounted  loosely  on  vertical  spindles  ar- 

ranged  m  a  double  row  of  sixty  or  more  in  a  long 

machine  resembling  a  fly  frame;  they  are  driven  by 

friction  and  receive  the  thread  from  bobbins  resting 

horizontally  in   wire  cages.     The  warper   combines 

the  threads  from   three  hundred   to   one  thousand 

spools. 

It  consists  of  the  following  parts:  a  creel,  or 
set  of  upright  racks  standing  side  by  side,  which  hold 
the  spools;  a  *^reed,"  or  series  of  vertical  wires  set 
m  a  rectangular  frame,  through  which  the  threads 
are  passed;  a  measuring  roll,  which  is  rotated  by  the 
threads  as  they  pass  over  it,  and  is  geared  to  a 
pointer  indicating  the  length  of  warp  that  has  been 
wound  off;  a  comb,  similar  to  the  reed,  which  lays 


TEXTILE  MACHINERY 


495 


the  threads  in  a  sheet  of  the  same  width  as  the  beam; 
and  the  beam,  on  which  this  sheet  is  wound. 

In  the  case  of  yarns  which  must  be  dyed  before 
weaving,  the  threads  are  condensed  into  a  narrow 
chain  and  wound  into  a  ball;  and  after  dyeing,  the 
chain  is  spread  out  into  a  sheet.  To  keep  the  threads 
from  tangling  in  the  chain,  and  to  simplify  the  piec- 
ing of  loose  ends  if  a  break  occurs,  the  comb  is  re- 
placed by  a  ** lease  reed,'*  in  which  each  wire  is  per- 
forated. Alternate  threads  pass  through  these  per- 
forations, while  the  others  pass  between  the  wires. 
At  intervals  of  five  hundred  to  one  thousand  yards, 
the  operator  raises  the  lease  reed,  lifting  up  half  of 
the  threads,  and  passes  a  cord  between  the  two  sheets 
of  warp  threads  from  one  side  to  the  other,  then  de- 
presses the  reed,  passes  the  cord  back  again,  and  ties 
the  loose  ends  together.  By  this  method  the  warp 
threads  are  maintained  in  their  correct  places 
through  all  the  rough  handling  involved  in  chaining, 
linking  or  balling,  and  dyeing. 

The  slasher.  Figure  196,  receives  the  thread  from 
a  number  of  warper  or  '*back''  beams,  sizes  it  to 
increase  its  strength  and  smoothness,  and  winds  it 
onto  the  warp  beam  of  a  loom.  The  figure  shows 
the  creel,  a,  holding  the  back  beams;  the  size  box,  b, 
through  which  the  warp  passes;  the  squeeze  rolls, 
c,  c,  which  remove  the  excess  of  size;  the  steam- 
heated  drying  drums,  d,  d^  about  seven  and  five  feet 
in  diameter,  respectively;  a  fan,  e,  to  assist  in  drying; 
dividing  rods,  f ,  f ,  for  separating  the  threads  which 
tend  to  stick  together  from  the  sizing;  a  tension  roll, 
g;   and  the  warp  beam,   h,   which   is   removed  and 


496 


THE  MECHANICAL  EQUIPMENT 


FIG.   196.      SLASHER 


mounted  in  a  loom  as  soon  as  it  contains  the  requisite 
length  of  yarn. 

Mechanism  of  the  Loom.— The  loom  makes  a  rec- 
tangular web  of  cloth  by  interlacing  two  sets  of  par- 
allel threads— the  warp,  running  lengthwise,  and  the 
weft  or  filling,  running  crosswise.     The  mechanism 
for  a  plain  loom  is  shown  in  Figure  197.     The  a\  arp 
threads,  a,  pass  from  the  warp  beam,  b,  to  the  cloth 
beam,  c;  alternate  threads,  as  for  example  the  odd- 
numbered  ones,  are  drawn  through  the  eyes,  d,  while 
the  even-numbered  ones  are  drawn  through  the  eyes,  e. 
A  shuttle,  f,  carrying  a  bobbin  of  filling  thread,' is 
thrown  back  and  forth  from  one  side  of  the  loom  to 
the  other,  and   after  each   traverse   the   position   of 
the  even-  and  the  odd-numbered  warp  threads  is  inter- 
changed,  so   that   the  filling  is   woven   between  the 
threads  of  the  warp.     Five  motions  are  required,  all 
derived  from  the  shaft,  g:  the  *^ shedding''  motion, 
which  separates  the  even-  and  the  odd-numbered  warp 
threads  by  alternately  raising  and  lowering  the  eyes 
d  and  e;  the  ^* picking''  motion,  which  throws  the 
shuttle  from  side  to  side,  each  traverse  being  called  a 
pick;  the  ** beating  up",  occurring  after  each  pick. 


TEXTILE  MACHINERY 


497 


which  drives  the  filling  firmly  into  place  by  a  quick 
motion  of  reed  h  towards  the  right;  the  *' let-off", 
which  unwinds  the  warp  from  the  beam,  b;  and  the 
** take-up",  which  winds  the  cloth  on  the  beam,  c,  at 
the  right  of  the  drawing. 

The  figure  shows  the  cams  and  the  gearing  for 
shedding  and  beating  up,  as  well  as  one  of  the  pick- 
motion  cams,  i.  The  rest  of  the  pick  motion  can  be 
seen  in  Figure  198,  which  is  a  front  view  of  the 
**lay,"  the  name  applied  to  the  swinging  frame  sup- 
porting the  reed  and  the  shuttle.  The  shuttle,  f,  is 
just  entering  the  shuttle  box,  k,  having  b^en  thrown 
across  from  the  box,  1,  by  the  picking  stick,  j,  actuated 
by  the  cam,  i. 

If  a  simple  design  is  to  be  repeated,  the  eyes  d  and 
e  are  carried  in  three  to  ten  or  more  sets,  instead  of 
two,  each  set  being  operated  by  its  own  *' harness/' 
For  more  complicated  patterns,  the  harnesses  are 
raised  by  levers  actuated  by  buttons,  or  *' risers," 
inserted  in  sin  endless  chain  which  is  moved  forward 
at  the  rate  of  one  link  per  pick.  This  device,  called 
a  *'dobby,"  is  fastened  to  the  upper  part  of  the  loom 
and  controls  the  design.  If  the  same  harness  arrange- 
ment is  to  be  repeated  for  a  number  of  picks,  as  in 
the  weaving  of  checks,  a  multiplier  chain  is  used. 
This  chain  is  started  by  the  arrival  at  the  working 
point  of  a  button  on  the  harness  chain.  The  harness 
chain  then  stops  until  a  button  on  the  multiplier 
chain  arrives  at  the  working  point  when  the  multi- 
plier stops  and  the  harness  chain  starts  on  again. 
When  more  than  one  color  of  filling  is  required,  a 
*'box  loom"  is  used,  having  several  shuttles  carried 


498 


THE  MECHANICAL  EQUIPMENT 


TEXTILE  MACHINERY 


499 


BACK 


FRONT 


V///////7//////////y/y/y////^^^^^ 


PIG.  197.     PLAIN  I/)OM,  LONGITUDINAL  SECTION 


FIG.   198.      PLAIN  LOOM,  SHOWING  LAY  AND  PICK  MOTION 


on  the  lay  in  a  tier  of  boxes,  which  is  elevated  or 
depressed  to  bring  the  proper  shuttle  into  action  by 
a  mechanism  similar  to  the  dobby. 

Weaving  Intricate  Patterns.— The  most  intricate 
patterns  afe  woven  on  a  loom  whose  ** shedding'*  is 
operated  by  a  Jacquard  machine,  Figure  199,  which 
controls  each  warp  thread  by  perforations  in  a  chain 
of  cards,  just  as  each  key  of  a  piano  is  controlled  by 
perforations  in  a  paper  roll  on  the  piano  player.  The 
elements  of  the  machine  are  a  set  of  needles,  a,  equal 
in  number  to  the  warp  threads  in  the  pattern;  hooks, 
b,  normally  resting  on  the  grating,  c;  a  rectangular 
block,  d,  called  the  cylinder,  supported  on  trunnions, 
d',  and  provided  with  holes  into  which  the  needles,  a, 
fit;  and  a  ** griff e,'*  or  set  of  bars,  e,  for  raising  the 
hooks. 

The  several  hooks  are  connected  by  strings,  g, 
with  the  eyes,  f,  through  which  the  warp  is  threaded. 
Three  cards  of  the  chain  appear  at  h.  Preceding  each 
pick  the  cylinder,  d,  moves  away  from  the  needles, 
makes  a  quarter  turn,  bringing  a  new  card  into 
action,  and  returns  to  the  position  shown.  This  mo- 
tion will  force  to  the  right  all  those  needles  for  which 
there  are  no  perforations  in  the  card;  and  the  loops 
in  these  needles  will  press  the  corresponding  hooks 
off  the  griff e,  so  that  when  the  griff e  is  raised  by  the 
shed  motion,  a  certain  number  of  the  warp  needles 
will  be  drawn  up  by  the  strings  or  ** harness,''  g, 
while  the  rest  will  remain  in  place.  As  may  be 
imagined,  the  cost  of  Jacquard  weaving  is  principally 
due  to  the  labor  involved  in  preparing  the  cards  and 
rigging  the  harness. 


500 


THE  MECHANICAL  EQUIPMENT 


TEXTILE  MACHINERY 


501 


Knitting  Machines.— Knitting  is  done  on  two  types 
of  machine:  spring  needle,  for  plain  work;  and  latch 
needle,  for  plain,  tuck,  ribbed,  and  other  varieties  of 
fabrics.  Both  types  produce  a  tubular  cloth,  forming 
the  stitches  in  spirals  around  the  fabric,  like  the 
threads  of  a  multiple  screw.  The  stitching  devices 
vary  with  different  manufacturers  and  are  compli- 
cated by  adjustments  for  changing  the  kind  of  stitch, 
but  the  essential  features  of  all  knitting  machines 
are  these:  a  single  or  a  double  row  of  hooked  needles, 
arranged  in  a  circle,  each  of  which  engages  one  loop 
of  the  working  edge  of  the  fabric;  cams  or  wheeFs 
for  moving  the  needles  and  fabric  relatively  to  each 
other  in  such  a  way  as  to  form  new  stitches;  and  a 
take-up  for  winding  the  knitted  fabric  on  rolls  or 
folding  it  in  cans  as  fast  as  it  is  made. 

Figure  200  shows  how  this  is  done  on  a  spring  needle 
machine.  The  various  wheels  used  to  direct  the 
thread  are  termed  a  feed;  four  of  these  feeds  are 
usually  attached  at  equal  intervals  around  the  ring,  a, 
on  which  the  circular  row  of  needles,  b,  is  mounted. 
The  needles  move  past  the  feed  from  left  to  right', 
as  indicated,  passing  in  turn  the  holding  wheel,  c, 
which  pushes  the  work  below  the  barbs  of  the  needles, 
sinker  burr,  d,  which  feeds  the  new  thread  under  the 
barbs,  presser  wheel,  e,  which  closes  the  barbs,  landing 
burr,  f ,  and  cast-off  burr,  g,  which  casts  off  the  old 
stitches  and  raises  the  new  ones  into  the  hooks  of  the 
needles.  By  noting  each  stitch  in  the  figure,  starting 
at  the  left  and  ending  at  the  right,  the  reader  can 
see  than  an  additional  course  of  stitches  has  been 
laid  during  the  passage  of  the  needles  through  the 


I 


502 


THE  MECHANICAl/  EQUIPMENT 


i 


TEXTILE  MACHINERY 


503 


feed.  The  latch  needle  machine  uses  two  rows  of 
needles,  one  set  vertically  and  the  other  horizontally, 
which  are  moved  in  and  out  at  each  feed  point  by 
means  of  cams. 

Finishing  Machinery. — Woven  fabrics  are  passed 
through  a  number  of  machines;  the  purpose  is  to  im- 
prove their  strength,  durability  and  appearance.  The 
fulling  mill,  used  for  partially  felting  woolen  goods, 
is  a  chest  containing  two  rolls  behind  which  is  a 
compartment  with  a  constricted  opening.  A  piece 
of  goods,  saturated  with  soapy  vater,  is  fed  between 
the  rolls,  and  the  ends  are  stitched  together.  The 
rolls  are  then  run  continuously  for  some  time;  the 
cloth  passes  between  them,  folds  up  in  the  compart- 
ment, is  squeezed  out  through  the  narrow  opening, 
drops  to  the  bottom  of  the  mill,  and  then  repeats 
this  cycle  Under  the  influence  of  pressure,  moisture, 
and  the  heat  developed  by  friction,  the  cloth  shrinks, 
at  the  same  time  becoming  firmer  and  stronger. 

The  short  threads  adhering  to  the  surface  of  cloth 
are  removed  by  a  singeing  machine,  which  consists  of 
a  frame  carrying  rollers  over  which  the  goods  are 
passed  from  one  folded  pile  to  another;  at  certain 
points  gas  flames  impinge  on  the  cloth,  or  heated 
copper  plates  come  in  contact  with  it,  and  by  proper 
legulation  of  cloth  speed  and  intensity  of  flame  all 
the  short  fibres  are  removed.  In  other  cases,  when  a 
nap  on  the  surface  of  the  goods  is  desired,  it  is  ob- 
tained by  a  **gig,"  a  machine  whose  principal  part 
is  a  cylinder  covered  with  special  thistles  or 
** teazles''  grown  for  the  purpose,  which  rotates  close 
to  the  surface   of  the  goods   to  be  napped.     After 


604 


THE  MECHANICAL  EQUIPMENT 


napping,  the  surface  is  made  uniform  in  a  shearing 
machine,  which  brushes  up  the  nap  and  then  trims  it 
to  the  correct  length  by  means  of  a  rotary  cutter  act- 
ing against  a  stationary  blade. 

Numerous  other  machines,  of  course,  are  used  in 
textile  making,  for  instance  in  the  processes  of 
bleaching  and  dyeing— but  as  these  are  in  the  nature 
of  special  equipment,  detailed  information  should  be 
sought  in  works  devoted  entirely  to  the  subject. 


INDEX 


Advantages  of  Grinding,  377 
Air  Furnace,  Section  of,  70 
Allowances,  Pattern,  37 
Alloys,  44 

Amazeen  Machine,  465 
Annealing,   150 
Armor  Plate  Planer,  295 
Arrangement  of  a  Shoe  Factory,  462 
Automatic  Bevel-Gear  Milling  Machine, 
355 

— Bevel-Gear  Planer,  356 

— Robbing  Machine,  352 

— Milling  Machine,  315 

— Screw  Machine,  234 
Automatic  Lathe,  Cleveland,  236 

—Fay,  240,   241 

— Gridley,  236,  237 

— Multi-Spindle,    238,   239 

— Principle  of,  232 

Band  Saw,  418,  419 
Beaters  and  Refiners,  447 
Belt-Driven  Open-Back  Press,  411 
Bench,  Saw,  Universal,  419-420 
Bending,  Pipe,  100 
Bevel-Gear  Milling  Machine,  355 

— Planer,  Automatic,  356 
Bevel  Gears,  337 

— Cutting  of,   354 
Binders,  Core,  55 
Blanchard  Lathe,   244,  432-433 
Blast,  Sand,  79 
Blocks,  Die,  110 

Blue-Printing  Machine,  Electric,  28 
Blue  Prints,  Issuance  of,  25 
Board  Drop  Hammer,  105 
Bolt  Threading  Machines,  365,  367 
Boot  and  Shoe  Machinery,  459 
Boring  Machine,  Horizontal,  258,  2C1, 
264 

— Portable,  263 

— Wilkinson's,   245 
Boring  Mill,  Table,  Drive  and  Tool  for, 
255 


^versus  Vertical  Planer,  249 

—Vertical,    Construction    of,    251 

— (Vertical)   versus  Lathe,  247 
Boring  Mills  Classified,  246 
Bottoming  Boom  Machinery,  474 
Box,  Change  Gear,  210 

— Tool,  Multiple,  225 
Brazing  and  Soldering,  135 

— Process,   136 
Breaker  Picker,  482 
Briggs'  Type  of  Milling  Machine,  314, 

315 
Broach  and  Dies,  404 
Broaches    and    Samples  of   Broaching 

Work,  402 
Broaching  Machine,  400,  401 

— Process,   398 

— ^Tools,  401 
Bryant  Chucking  Grinder,  394 
Buffing  and   Polishing,   397 

— Machine,   Naumkeag,  479 
Building  Method,  2 

— Tools  used  in,  4 

— Type,  for  Special  Work,  4 

^Type      used      in      Manufacturing 
Work,  7 
Buildings,  Foundry,  45 
Bullard  Mult-au-matic  Vertical  Lathe, 

256.  257 
Butt  Welding  Machine,  124 

Carbonizing,   153 
Carbon  Steel,   171 

— Heating  of,   144 
Car-Wheel    Lathe,    216 
Cast  Steel,  43 
Castings,  Cleaning  of,  78 

— Defective,  76 

— Pickling  of,   79 

— Tumbling  of,   78 
Chain  Stitch  Mechanism,  469 

—McKay,  477 
Change-Gear  Box,  210 
Changes  in  Drawings,  26 

505 


506 


INDEX 


INDEX 


507 


Checking  Designs,  24 

ChiUed  Iron,  42 

Chuck,  Lathe,  213 

Chucking  Grinder,  394 
— Machine,  465 

Circular  Saw,  418 

Classes  of  Welding,  118 

Classification  of  Boring  Mills,  246 

Cleaning  of  Castings,  78 

Cleveland  Automatic  Lathe,  Top  View, 

Cold  Trimming  of  Forgings,  115 
Collapsing  Die  Head,  368 

— Tap,  368 
Collection  of  Milling  Cutters.  310 
color  and  Temperature  Scale  for  Tool 

Hardening,   152 
Column    and    Knee    Type    of    Milling 

Machine,   318 
Comb,  484 
— Noble,  491 

S!"i*°!2"°    Production    Methods,    11 
Construction  of  Shaper,   299 

— Vertical  Boring  Mill    251 
Continuous  Rotary  Feeding,  828 
Contour  Gauge,   169 
Cope,  Description  of,   56 
Copying  Lathe,  432-433 
Core  Binders.  55 

— Prints,  Pattern,  38 
Cores,    55 

Correct  Mounting  For  Grinding  Wheel, 

384 
Cotton  Carding  Machine,  483 
— Spinning  Machinery,  481 
Crank  Planer,  289 
Cross-Section^of  Head  Stock.  208 
Crucible  Furnace  for  Melting  Brass    74 

—Gas-Fired  Heating  Furnace.  146 
Cupola,  Method  of  Melting  in,  65 

— Section  of,  67 
Cupolas,  Dimensions  of,  69 
Curve,  Heat-Temperature.  142 
Cutlery,  Milling,  310 
Cutter,  Rag,  440 
Cutters  and  Dusters,   439 
— Heavy-Gauge  Milling,  186 
— Milling,    180 

—Standard  Types  of,    181,  185 
Cutting  Areas.  Effective,  250 
— Bevel  Gears.   354 
— Gear  Teeth.    335 
— Helical   Gears,    353 
— Lubricants,   198 
— r.crew  Threads,   364 
Cutting  Gear,  Formed-Tooth  Principle, 

— Generating  Principle  of,  343 


— Template  Principle  of,  341 
Cutting  Boom  Machinery,  464 
S"*!?"*'™^'***'  **"  Lathes,   371 
rl^A^  ^^**^^'  Material  used  in.   171 
Cylinder  Paper   Machine,   455 


Defective  Castings,   76 

Department.    Drafting,    Functions    of. 

— Personnel  of,  18 
Description  of  Cope,  56 
— Drag,  56 
— Ladles,  75 
Desi^  Of  Plant  Equipment,   14 

— Product.   14 
Designs,  Checking,  24 
Development  of  Grinding  Process.  377 
— Lincoln  Miller,  316 
— the  Lathe.  200 
Die  Blocks,  110,  118 

— Head,  Collapsing,  368 
— Sinking  Machine,  320 
— Working,  109 
Dies,  404,  405 

— and  Their  Action,  408 
— Drop  Hammer.  107 
— Threading.  195 
— Use  of,   195 
Digesters  and  Washers    441 
Dimensions  of  Cupolas,' 69 
Distinction   between    "Building"    and 

Manufacturing,    1 
Drafting  Lists,   15 

Drafting  Department,  Functions  of  the, 

— Personnel  of,   18 
Drafting  Boom  Equipment,  26 
— Location   of,   27 
— Policies  of.    19 
— Practice,   23 

—Supplementary   Functions  of    17 
Drag,  Description  of,  56 
Drawing  Frame,  485 

— Process,  99 
Drawings,    15 

— Changes  in,  26 
— Piling  ot,  25 
Drill  Column,  Section  of,  275 
— Multiple-Spindle,   277,   278 
— Radial,  Pull  Universal',  277    278 
— Sensitive,  266,  267 
Drilling  Jigg,  279 

^"^    ^eT'    ^^"'''^''''^    ^P"'«»>t.    267. 
— Work,   281 

Drills.  Radial.   273,   275 
^Types  Of,  188 


— Use  of,   187 
Drive.    Rack-and-Pinion,   286 
Driving  Pulley,  Single.  212 
Drop  Hammer,   103 

— Hammer  Dies,  107 

— Table  Moulder,  431 
Drop  Forging  Operation.  114 

— Section  of,   110 

— Stages  of  a,  112 

— Utility  of,   102 
Drop  Forgings,  Pickling.  115 
Duster,  Taylor,  440 
Dusters  and  Cutters,  439 

Early  Methods  of  Cutting  Screws,  360 

— Types  of  Planers,  284 
Effective  Cutting  Areas  on  Planer  and 

Boring  Mill.  250 
Electric    Blue-Printing    Machine,    28 

— Furnace,   75 

— Resistance  Welding,   122 
Elements    of    Spring    Needle    Knitting 

Machine,    502 
Elevation  of  Fourdrinier  Machine,  449 
Engine  Lathe,  The,  204.  206 

— versus  Turret  Lathe,  220 
Equipment,  Drafting  Room,  26 

— Foundry,    45 

— Machine,  for  Tool  Room,  159 

— Plant,  Design  of,  14 
Estimating,  17 

Example  oi  Profiling  Work,  323 
Extrusion  Process,   100 

Facing,  Mould,  54 

Factory,  Shoe,  Arrangement  of.  462 

Fastenings,  Sole,  Types  of,  463 

Fay  Automatic  Lathe,  240,  241 

Feed  Motions.  290 

Feeding,   Continuous-Rotary,   328 

Fellows  Gear  Shaper,  348,  349 

Fibres  and  Processes.  481 

Filing  of  Drawings,  25 

Fillets,  Pattern,  38 

Finishing   Machinery,    456,    503 

— Room  Machinery,   478 
First  Screw  Cutting  Lathe,  202 
Fixtures  and  Jigs,   160 
Flame  Welding,  Gas,  130 
Flat  Turret  Lathe,  Hartness.   229 
Fly  Frame,  485,  486 
Forge,  The,  Description  of,  81 
Forging  Machine,  96 

— Methods,    80 

— Press,   1100-Ton  Hydraulic.  96 

— Rolls,  96 

— Tools.  Hand.   83.   85 
Forging,  Drop,  Section  of,  110 


— Stages  of  a,  112 

— Utility  of,   102 
Forging,  Hand,  80 

— Operations  of,  86 
Forgings,  Cold  Trimming  of,   115 

— Drop,  Pickling  of,  115 
Formed-Tooth    Principle    of    Gear^Cut* 

ting,   338 
Forming  Tools,  Single-Edged,  179 
Foot  Press,  4ir 
Foundry  Buildings  and  Equipment,  45 

— Cores  for  Moulding  in,  55 

— Loam  used  in,  54 

— Melting,  Pouring  and  Cle.'  ning  in, 
65 

— Metals,  41 

— Moulding  Materials  used  in,  52 

— Moulding  Sands  used  in,  53 

— Mould-Making  in,  58,  60 

— Transportation  in,  49 
Fourdrinier  Machine,  Plan  of,  450 

— Paper  Machine,  449 
Frame,   Drawing.   485 

— Ply,  485,  486 
FuU  Universal  Radial  Drill,  277 
Function  of  Pattern  Shop,  30 
Functions  of  Drafting  Department,   13 

— Drafting  Room,  17 

— Tool  Room,   156 
Furnace,  Air,  70 

— Air,  Section  of,  70 

— Crucible,  for  Melting  Brass,  73 

— Crucible  Gas  Fired  Heating,  146 

— Electric.  75 

— Gas.  71 

— Oil,   71 

— Oil,  Tilting  Type.  73 

— Open  Hearth.  71 

— View  of  Open  Hearth,  72 

Gang  Milling  Cutters,  Heavy,  186 

—Mills.   185 

—Saw,  423 
Gardner    Horizontal    Disc    and    Ring 

Grinder,  385 
Oas  Flame  Welding.  130 

— Welding,  Uses  of,   130 

— Weldings.   Advantages  of,   133 
Gated  Patterns,  34 
Gauge,  Contour,  169 

— Lathe,  432 
Gauges,  Types  of,  165,  167 
Gauging,   164 
Gear  Box,  Change-,  210 

— Planer,    349 

— Teeth,  Cutting,  335 
Gear-Cutting,    Formed-Tooth   Principle 
of.  338 


508 


INDEX 


— Generating  Principle  of,  343 
— Template  Principle  of,  341 
Gears,  Bevel,  337 

— Bevel,  Cutting  of,  354 
— Helical,  337 
— Helical,  Cutting  of,  353 
— Spur,  336 
— Worm,  337 
Gear-Staaper,  Fellows.  348.  349 
— Head,  Section  of,  ^51 
— Slide,  128 
Generating  Principle   of  Gear- Cutting, 

343 
Gisholt  Lathe,   226,   227 
Grading  of  Grinding  Wheels,  381 
Gray  Iron  Foundry,   Plan  and  Section 

of  41,  47 
Gridley  Automatic  Lathe,  236,  237 
Grinder,  Bryant  Chucking,  394 
— ^Horizontal,  Disc  and  Ring,  385 
— Surface,  388 
— Tool,   395 
— Wood-Pulp,  445 
Grinding,  Advantages  of,  377 
— Machine,   Heald,   394 
— Machines,    391 
— Machines,  Types  of,  386 
— Process,  Development  of,  377 
— Wheel,  Correct  Mounting  for,  384 
— Wheel   Stand,   385 
Grinding  Wheels,   380 
— Grading  of,   381 
— Mounting  of,   383 
— Selection  of,  382 
Gun  Lathe,  Large,  216 

Hammer,  Board  Drop,  105 

— Drop,   103 

— Power,  91,  93 

— Steam,  Work  of,   88 

— Upright  Helve,  93 
Hand    p'^h    Automatic    Turret    Lathes, 
221 

— Milling  Machine,  312 

— Operated  Rock  Over  Molding  Ma- 
chine, 62 

— Operated  Turret  Lathes,  223 

— Planer,  425 
Hand  Forging,  80 

— Operations,  86 

— Tools,  83,  85 
Hardening,  140 

, — by  Quenching,  147 
Hartness  Flat-Tarret  Lathe,  230 
Head,  Surfacer,  Section  of.  425 
Headers  and  Upsetters,  94 
Head-Stock,  207 

— Cross  Section  of,  208 


Heald  Internal  Grinding  Machine,  394 
Heat  Temperature  Curve,  142 

— Treatment  Processes,  139 
Heating  of  Carbon  Steels,   144 

— Steel,  114 
Heavy  Duty  Drill  Presses,  270,  271 

— Gang  Milling  Cutters,   186 
Helical  Gears,  337 

— Cutting  of,  353 
Henry  Maudslay  and  Modern  Tools,  200 
High-Speed  Steels,  172 
History  of  Shoe  Machinery,  459 
Hobbing  Machine,   351 

— Automatic,   352 
Holders,  Tool,  Multiple,  178 
HoUow  Chisel  Mortiser,  435 
Horizontal  Boring  Machine,  258,  261, 
264 

— Disc  and  Ring  Grinder,  385 
Hydraulic  Forging  Press,  96 

— Press,  94 

Indexing  Heads  for  Milling  Machines, 
326 

— Threading  Tool,  373 
Interchangeable  Production  System,  6 
Interna)   Grinding  Machine,   394 
Iron,  Chilled.  42 

— Gray,  41 

— Malleable,  43 

— Pig,  Storage  of,  49 
Issuance  of  Blue  Prints,  25 

Jacqaard  Machine,  500 
Jigs  and  Fixtures,  160 
— Drilling,   279 

Key-Seating  Machine,  307 
Knitting  Machines,  501 
Knuckle- Joint  Press,  411 

Ladles,  Description  of,  75 

La  Grange-Hoho  Process,   127 

Large  Double   Frame   Steam  Hammer, 

90 
Lathe,  Blanchard,  244,  432-433 

— Bullard     Mult-au-matic     Vertical, 
256,  257 

— Car  Wheel,  216 

— Chuck,  213 

— Cleveland  Automatic,  236 

— Development  of  the,  200 

— Engine,  204,  206 

— Fay  Automatic,  240,  241 

— Flat  Turret,  229 

— Gauge,   432 

— Gisholt,  226,   227 

— Gridley  Automatic,  236,  287 


INDEX 


509 


— Gun,  Large,  216 

— Lo-Swing,  241,  243 

— Operations,  215 

— Speed,  203 

— Standard  Engine,   206 

— ^Turret  versus  Engine,  220 

— versus  Vertical  Boring  Mill,  247 

— Vertical  Turret,  248 

— Warner  and  Swasey,  228 
Lathe-Planer,  The,   174 
Lathes,  Automatic,  Principle  of,  232 

— Mounting  the  work  on,  212 

— Multi-Spindle       Automatic,       222, 
238,  239 

— Special,  215 

— Thread-Cutting  on,  371 

— Turret  and  Automatic.  219 

— ^Turret,  Hand  Operated,  223 
"Lay    and    Pick"    Motion    of    Plain 

Loom,  498 
Lincoln   Miller,  Development  of,   316 

— Type  of  Milling  Machine.  312 
Linen  and  Silk  Preparation,  493 
Lists,  Drawing,   15 
Loam,  54 
Location  of  Drafting  Room.  27 

— Pattern  Shop.  30 
Lock  Stitch  Mechanism,  470 
Log-Mill,  421-422 
Loom,  Mechanism  of,  496 

— Plain,    "Lay   and   Pick"    Motion. 
498 

— Plain,    Longitudinal    Section     of, 
498 
Lo-Swing  Lathe,  241,  243 
Lubricants,  Cutting,  198 

McKay  Chain  Stitch  Mechanism,  477 

— Sewing  Machine,  473 
Machine,  Automatic  Hobbing,  352 

Bolt-Heading,   Upsetting,   and   Forg- 
ing, 95 

— Bolt-Threading.  365,  367 

— Boring,   Horizontal,  258.   261 

— Boring,  Wilkinson's.  245 

— Broachinig.  400.  401 

— Cotton-Carding,  483 

— Die-Sinking,   320 

— Equipment,  Tool  Room,  159 

— Fourdrinier,  Paper,  449 

— Hobbing.   351 

— Jacquard,  500 

— Key-Seating.  307 

— Milling,  Planer  Type  of.  329 

— Moulding.  62 

— Operations  of  Shoe  Manufacture, 
461 

— Pipe-Threading,  369,   370 


— Profiling,  320.  322 

— Spinning,  485 

— Thread-Milling,  375 

— Thread-Rolling,  375 

— Vertical-Slotting,    306 
Machine,  Milling,  Automatic,  315 

— Briggs  Type  of,  314,  315 

—Hand,  312 

— Origin  and  Development,  309 

— Planer  Type  of,  331 

— Universal,  324,  325 

— Vertical,    320 

— Work  of,  308 
Machine  Moulding,  60 
Machinery,  Boot  and  Shoe,  459 

— Bottoming  Room.   474 

— Cotton-Spinning.  481 

— Cutting-Room.  464 

— Finishing.   456.  508 

— Finishing-Room.    478 

— of  Stock  Fitting  Room,  472 

— Paper,   438 

— Pattern-Shop,  40 

— Rag,   438 

— Stitching-Room,  468 

— Textile,   481 

— Weaving,  494 

— Wood-Pulp,  444 

— Wool-Spinning,  489 

— Worsted- Spinning.    490 
Machines,  Automatic  Screw,  234 

— Boring,  Horizontal,  264 

— Boring,  Portable  Type,  263 

— Grinding,  391 

— Grinding,  Type  of.  386 

— Knitting,   501 

— Miscellaneous,  434 

— Paper,  448 

— Woodworking,  Types  of,  416 
Making.   Mould,   58 
Malleable   Iron,   43 
Manufacturing  Method,  3 

— Tools,   Used  in,  5 
Marking  of  Patterns.  38 
Matcher,  Six-Head  Planer  or,  429 
Material,  Pattern,  36 

— Used  in  Cutting  Tools.    171 
Materials,  Moulding,  Foundry,  52 
Maudslay,  Henry,  200 

— Screw-Cutting  Lathe,  First,  202 
Mechanism,  Chain  Stitch,  469 
— Lock  Stitch,  470 
— of  the  Loom,  496 
Melting,  Cupola  Method  of,  65 

— Pouring  and  Cleaning  in  Foundry, 
65 
Metal  Pouring,  76 
Metals,  Foundry,  41 


\ 


510 


INDEX 


INDEX 


511 


Method  of  Melting,  Cupola,  65 

— The  Building,   2 

— The  Manufacturing,   3 
Methods,  Forging,  80 

— of    Cutting   Screws,    360 

— Production,    Combination,    11 
Mill,  Log,  421-422 
MiUer,  Vertical,  319,  320 
Milling  of  Long  Spirals,  327 

— Operation  Speeds  and  Feeds,   187 

— Process.  Advantages  of,  308 

— Screw  Threads,  374 

— Teeth  of  Spur  Gear,  327 

— Thread,    Machine,     375 

— Wood,    Machine,   435 
Milling  Cutters,  180 

— Collection   of,   310 

— Types  of,  185 
Milling  Machine,  Automatic,  315 

— Automatic  Bevel  Gear,  365 

— Briggs  Type  of,  314,  315 

— Hand,  312 

— Lincoln  Type  of,  312 

— Origin  and  Development,  309 

— Plain,  Column-and-Knee  Type,  318 

— Planer  Type  of,  329,  331 

— Universal,   324,  325 

•^Vertical,    320 

— Work  of  the,  308 
Milling  Machines,  Indexing  Heads  for. 

326 
Mills,  Boring,   Classiflcation  of,  246 

— Boring,  Vertical,  251,  253 

— Gang,    185 
Miscellaneous  Machines,   434 
Modem  Planer,  The,  284 
Modem  Development  of  Lincoln  Miller. 
316 

— Tool  Room  a,  155 
Mortiser,   Hollow  Chisel,  435 
Motions,  Feed,  290 
Mould,  Making  a,  58 
Moulder,  Drop  Table,  431 
Monlders  and  Shapers,  424 

— Time  of,  30 

— Tools  of,  57 
Moulding,   Machine,  60 

— Sands,  53 
Moulding  Machine  and  Sectional  View, 
62 

— Hand-Operated  Rock  Over,  62 
Moulds,  Facing  used  for,  54 
Monnting  of  Grinding  Wheels,  383 

— for  Grinding  Wheel,  384 

— Work  on  Lathes,  212 
Mule,   Spinning,   488 
Mult-an-matic     Vertical     Lathe, — ^Bul- 
lard.  257 


Multiple  Box  Tool,  225 
— Tool-Holders,   178 
Multiple-Spindle  Drill,  277,  278 
Mnlti-Spindle  Automatic  Lathes,    222, 

238,  239 
Mnshet,  or  Self-Hardening  Steel,  172 

Naumkeag  Buffing  Machine.  479 

Noble  Comb,   491 

Norton  Grinding  Wheel  Stand.  385 

Oil  Furnace,  Filling  Type  of,  73 

— or  Gas  Furnace,  71 
Open-Hearth  Furnace,  71 
Open-Side  Planer.  293 
Operation  of  Shaper,  299 
Operations,  Hand-Forging,  86 

— in  Shoe  Manufacturing,  Machine, 
461 

— Lathe,  215 
Origin    and    Deyelopment    of    Milling 

Machine,  309 

Fainting  of  Patterns,  38 
Paper  Mact>ine.   Cylinder,  455 

— Machine,   Fourdrinier,   449 

— Machinery,  438 

— Machines,  448 
Pattern  Allowances,  37 

— Core  Prints,  38 

— Fillets  for,  38 

— Makers,  Time  of,  30 

— Material,   3(J 

— Records,  40 

— Storage.  39 
Pattems,  Gated,  34 

— Intricate,  Weaving  of,  499 

— Marking  and  Painting  of,  38 

— Splitting  and  Warping  of.  38 

— Types  of,  32,  35 
Pattern  Shop,   Function   and  Location 
of,  30 

— Machinery.  40 
Personnel  of  Drafting  Department,  18 
Picker,  Breaker,  482 
Pickling  Drop  Forgings,   115 

— of  Castings,  79 
Pig  Iron,  Storage  of,  49 
PlUar   Press,   411 
Pipe-Bending,    100 

— Threading  Machine,  369,  370 
Plain  Loom,  Lay  and  Pick  Motion,  498 

— Longitudinal  Section,  498 
Plan  of  Fourdrinier   Machine.   450 
Planer,  Armor  Plate.  295 

— Automatic  Bevel  Gear,  356 

— Crank.  289 

— Gear,   349 


— ^Hand.  425 
—Open  Side,  293 
— Rotary,  332 
— Screw-Driven,  296 
—standard  Type  of,  285,  2«7 
— The  Modern,  284 
—Thirty-Foot,    295 
—Type  of  Milling  Machine    329 
—versus  Vertical  Boring  Mill,  249 
Planers,  331,  424 

— Early  Types  of,  284 
—Special  Types  of,  292 
Plant  Equipment,  Design  of,  l* 
Plate  Planer,  Armor,  295 
Policies  of  Drafting  Room.  19 
Polishing  and  Buffing,  397 
Portable  Boring  Machines,  263 
Post,  Tool,  214 
Pouring,   Metal,  76 
Power  Consumption  of  Saws,  424 

— Hammers,  91,  93 
Practice,  Drafting  Room,  23 
Preparation  of  Silk  and  Linen,   493 
Press,  Belt-Driven,  Open-Back,  411 
—Drill,  Upright,  267,  268 
— Foot,  411 
— Hydraulic,  94 
— Knuckle-joint,    411 
— Pillar.  411 

— Trimming,  106  „„«    oti 

Presses,  Drill,  Heavy-Duty,  270    271 
Pressure  Welding  by  H«imniering    119 
Principle  of  Automatic  Lathes,  232 

-Template,  of  Gear-Cutting.  341 
Process,  Brazing,    136 
— Broaching,  398 
— Drafting,  99 
—Extrusion,   100 
—Grinding,  Development  of,  377 
—La  Grange-Hoho,  of  Welding.  127 
—Milling,  Advantages  of,  308 
—Rolling,  97 
Processes,  Heat  Treatment,  139 

— Types  of,  409 
Product,  Design  of.  14 
Production   Methods,   Combination.    11 

—System.  Interchangeable,  6 
Profiling  Machine,  320,  322 
— Work,  Example  of,  323 
Pulley,   Single  Driving,  212 
Pulling-Over  Machine,  47  d 
Punches  and  Dies,  405 
— Use  of,    195 

Quenching,  Hardening  by.  147 

Rack-and-Pinion  Drive    286 
Radial  Drill.   Full  Universal.  277 


—Drills,  273,  275 
Bag  Cutter,  440 

— Machinery,  438 
Eeamers,  Types  of,  192 

— Use  of,  191 
Records  of  Work  Done,   16 

— Pattern,  40 
Beflners  and  Beaters,  447 
Belation  of  Tool  Room  to  Shop.  155 
Resistance  Welding,  Electric,   122 
Best,   Slide,   210  ,    ^„^ 

Boiling  Machine,  Thread,   375 

— Process,  97 

— Threads,    376 
BoUs,  Forging,  96 
Botary  Feeding,   Continuous,   a^o 
— Planer,   332 

Safety,  414  ,     ^^o 

Samples  of  Broaching  Work,  402 

Sand  Blast,  79 
Sands,  Moulding,   53 
Saw,  Band,  418,  419 

— Circular,   418 

— Gang,  423 

— Swing  Frame,    421-422 
Saw  Bench,  Universal,  419-420 

Saws,  417 

— Power  Consumption  of,  4i!4 

— Use  of,  197  ,  „     J 

Scale,   Temperature,    for   Tool-Harden- 

ing,   152 
Screw   Machines.    Automatic,   234 
Screw-Driven  Planer,  296 
Screw  Threads,  Cutting  of.  364 
— Milling.   374 
— Standard,   362 
— Standardization   of,    361 
— ^Types  of,  361 
Screws,   Methods   of  Cutting,  360 
Section  of  Cupola,  67 
— Drop   Forging,    110 
— Gear-Shaper  Head,  351 
— Plain  Loom,  498 

Radial  Drill  Column,  275 

— Shaper,  300 
— Surfacer  Head,  425 
Sections  of   Standard   Screw  Threads, 

362 
Section  of  Grinding  Wheels,  382 
Self-Hardening  Steel,   148,   172 
Sensitive  Drill.  The,  266,  267 
Sewing  Machine,  McKay,  473 
Shaper,  Construction  and  Operation  of, 

299 
—Gear,  Fellows,  348,  349 

(or  Slotter),  Vertical,  305 

— Section  of,  300 


fl 


512 


INDEX 


INDEX 


513 


— Standard,  298 
— Traversing,    302,    303 
Shapers,  424 
Shears,  Use  of,   197 
Shoe  Factory,  Arrangement  of,  462 
Shoe  Machinery,  459 

— History  of,  459 
Shoe  Manufacture,  Machine  Operations 

of,  461 
Shoes,  Types  of,  462 
Silk  and  Linen  Preparation,   493 
Single  Driving  Pulley,  212 
Single-Edged  Forming  Tools,   179 
Single-Frame  Steam  Hammer,  90 
Six-Head  Planer  or  Matcher,  429 
Slasher,  496 
Slide,  Gear-Shaper,  128 

— Rest,   210 
Slotter,  Vertical,  or  Shaper,  305 
Slotting  Machine,   Vertical,    306 
Soldering  and  Brazing,    135 
Sole  Fastenings,  Types  of,  463 

— ^Rounding   Machine,    473 
Special  Lathes,  215 

— Types  of  Planers,  292 
Speed,  High,  Steels  of,   172 

— Lathe,  The,  203 
Speeds,  207 

— and  Feeds,  Milling  Operation,  187 
Spindle  and  Tail  Stock,  209 
Spinning  Machine,  485 
Spinning  Machinery,  for  Cotton,  481 
— for  Wool,   489 
— for  Worsted,  490 
Spinning  Mule,  488 
Spirals,  Milling  of  Long,  327 
Splitting  and  Warping  of  Patterns.  38 
Spring  Needle  Knitting  Machine.   502 
Spur  Gears,  336 
Stages  of  a  Drop  Forging,  112 
Stand,  Grinding  Wheel,  385 
Standard  Engine  Lathe,  206 

— Screw  Threads,   Section  of,   362 
— Shaper,  298 

— Type  of  Planer,   285,   287 
— Types  of  Milling  Cutters,   181 
— Upright  Drill  Press,  267,  268 
Standardization  of  Screw  Threads,  361 
Standards,  15 
Steam  Hammer,  90 

— Work,   88 
Steel,  Carbon,  171 
— Cast,  43 
— Heating,  114 

— Mushet,  or  Self -Hardening,  172 
— Properties,  Variability  of,   137 
— Taylor-White,    149 
Ste«l8»  Carbon.  Heating  of,  144 


— High-Speed,  172 

— Self-Hardening,   148 
Stitch,  Chain,  Mechanism  of,  477 

— Lock,  Mechanism,  470 
Stitching-Room  Machinery,  468      *• 
StocV  Fitting  Room  Machinery    472 

— Head,  207 

— Head,  Cross  Section  of,  208 

— Spindle  and  Tail,  209 
Storage,  Pattern,  39 

— Pig-iron,   49 
Store-Boom,  Tool,  158 
Super  Calender,  456 
Surface  Grinders,  388 
Surfacer  Head,   Section  of,  425 
Surfacers,   424 
Swing-Frame  Saw,   421-422 
System,  Production,  Interchangeable,  6 
Systems  of  Tooth  Forms,  334 

Table,   Drop,    Moulder,    431 

— Drive  and  Tools  for  Boring  Mill 
255 
Tail  Stock,  209 
Tap,  Collapsing,  368 
Taps,  Use  of,  191,  193 
Taylor  Duster,   440 
Taylor-White  Steel,  149 
Teeth,  Gear,  Cutting,  335 

— Milling,    for  Spur  Gear,   327 
Tempering,   151 

Template    Principle    of    Gear-Cutting 
341  * 

Textile  Machinery,  481 
Thermit  Welding,  133 
Thread-Cutting  on  Lathes,  371 
Threading,  Bolt,  Machine,  365.  367 
— Dies,   195 

— Pipe,  Machine,  369,  370 
— Tool,  Indexing,  373 
Thread-Milling  Machine,  375 
Thread-Boiling  Machine,  375 
Threads,    Rolling,    376 
Threads,  Screw,  Cutting  of.  364 
— Milling  of,  374 
— Standard,   362 
— Standardization   of,   361 
— ^Types  of,  361 
Time  and  Power  in  Electric  Resistance 

Welding,   123 
Time  of  Moulders,  30 

— Pattern-Makers,  30 
Tool,  Indexing  Threading,  373 
— Multiple  Box,  225 
— Post,   214 
Tool-Grinders,   395 
Tool-Holders,  Multiple,   178 


Tool    Boom,    a    Modern    Development, 
155 

— Functions   of,    156 

— Its  Relation  to  the  Shop,  155 

— Machine  Equipment  for,    159 
Tools,  Available,  24 

—Boring-Mill,  255 

— Broaching,  401 

— Forming,  Single-Edged,  179 

— Hand  Forging,  83,  85 

— Lathe  and  Planer,  175 

— Milling  Cutters,    180 

— Small,  Moulders',  57 

— Used  in  Building,  4 

— Used  in  Manufacturing,  5 
Tool  Store  Boom,  The,   158 
Tooth  Forms,  Two   Systems  of,  334 
Transportation,   Foundry,   49 
Traversing  Shaper,  The,  302,  303 
Trimming,  Cold,  of  Forgings,  115 

— Press,    106 
Tumbling  of  Castings,  78 
Turret  and  Automatic  Lathes,  219 
Turret  Lathe  versus  Engine  Lathe,  220 

— Vertical,   248 
Turret   Lathes,    Hand   and   Automatic, 
221 

— ^Hand-Operated.  223 
Turret  Principle,  The,  219 
Type  of  Planer.  Standard,  285,  287 
Type  of  Building  for  Special  Work,   4 

— Used    in    Manufacturing    Work,    7 
Types  of  Drills,  188 

— Gauges,   165,   167 

— Grinding  Machines,   386 

— ^Inserted    Tooth    Milling    Cutters, 
185 

— Lathe  and  Planer  Tools,  175 

— Milling  Cutters,  181 

— Patterns,  32,  35 

— Planers,  Early,   284 

— Planers,  Special,  292 

— Processes,  409 

— Reamers,  192 

— Screw  Threads,  361 

— Shoes,   462 

— Sole  Fastenings,  463 

— Welds,   121 

— Woodworking  Machines,  416 


Universal  Milling  Machine,  324,   325 
Use  of  Tools  in  Building,  4 
Upright  Helve  Hammer,  93 
Upsetters,   Headers   and,  94 
Variability  of  Steel  Properties,   137 
Vertical  Boring  Mills,  251,  253 

— Miller,  319,  320 

— Milling  Machine,  320 

— Shaper  (or  Slotter),  305 

— Slotting  Machine,  306 

— Turret  Lathe,  248 

Vertical  Boring  Mill,   Construction  of, 
251 

— versus  Lathe.  247 

— versus  Planer,  249 
View  of  Open  Hearth  Furnace,   72 

Warner  and  Swasey  Lathe,  227 
Warping  and  Splitting  of  Patterns,  88 
Washer,  443 

Washers   and  Digestors,   441 
Weaving  of  Intricate   Patterns,   499 

— Machinery,   494 
Welding,   87 

— Butt,  Machine,  124 

— Classes  of,  118 

— Electric  Resistance,   122 

— Gas  Flame,  130 

— ^Lf  Grange-Hoho  Process,   127 

— Pressure,  119 

— Thermit,   133 
Welds,  Types  of,  121 
Wheels,  Grinding,  380 

— Grading  of,   381 

— Mounting  of,  383,  384 

— ^Selection  of,  382 
Whitworth  Quick-Return-Motion 

(Shaper),  303 
Wilkinson's  Boring  Machine,  245 
Wood-Milling  Machine,  435 
Wood-Pulp  Grinder,  445 

— Machinery,  444 
Woodworking  Machines,  Types  of,  416 
Wool-Spinning  Machinery,  489 
Work  Done  on  Drill  Press,  281 

— of  the  Milling  Machine,  308 
Worm  Gears,  337 
Worsted-Spinning  Machinery,  490 


Date  Due 


-m-^ 


iDGl3 


l96f^ 


Wt^ 


BBSHI 


i^uv  1/  1924 


U  ^s^  0^37:. 


UUL 1 5 1994 


COLUMBIA  UNIVERSITY  LIBRARIES 


0041394747 


END  OF 
TITLE 


